Inkjet recording apparatus and inkjet recording method

ABSTRACT

An inkjet recording apparatus, includes: a black ink ejecting portion configured to eject a black ink containing a self-dispersion pigment; color ink ejecting portions configured to eject, respectively, a cyan ink, a magenta ink and a yellow ink which contain a polymer emulsion containing a polymer fine particle containing a coloring material which is insoluble in water or slightly soluble in water; and a recording-controlling unit configured to control recording. When the recording medium is optically transparent and is provided, on a transparent base material thereof, with an ink accepting layer, the recording-controlling unit controls recording on the recording medium such that the color ink ejecting portion is used for recording a monochrome image and a color image which has a plurality of colors, leaving the black ink ejecting portion substantially free from being used.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation of Application No. PCT/ JP03/ 07996, filed onJun. 24, 2003.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an inkjet recording apparatus and aninkjet recording method which use a pigment ink. More specifically, thepresent invention relates to the inkjet recording apparatus and theinkjet recording method which can bring about a high quality image thatis excellent in ink absorbing property and fixing property and has goodcolor tone, can bring about an image that is excellent in image rigiditysuch as water-proof and light-proof, is excellent in storage stabilityand is excellent in ejection stability free from head's clogging in theprinting.

2. Description of the Related Art

From its advantages such as low noise, low running cost and the like, aninkjet recording apparatus is remarkably pervaded, and a color printercapable of printing color image on plain paper in addition to an inkjetrecording medium is more and more placed on the market. It is, however,very difficult to meet all required properties including colorreproducibility of an image, durability, light resistance, imagedryness, character feathering, color boundary bleeding (for short, colorbleeding), both-side printing property, ejection stability, and thelike. With this, the ink used is selected based on a preferentialproperty for a specific application. Especially, meeting the aboverequired properties are difficult for the printer for high-speed plainpaper printing.

Generally, with its principle component of water, the ink for the inkjetprinting contains a coloring agent, and further contains a wetting agentsuch as glycerin and the like for clogging prevention. As the coloringagent, dye is used in view of its excellent coloring property andstability. An image obtained by using a dye ink does not have good lightresistance, waterproof, and the like. The waterproof is improved to acertain extent by improvement of inkjet record paper having an inkabsorbing layer, which improvement does not, however, apply sufficientlyto the plain paper.

Recently, for solving the above problems, a pigment ink using ascoloring agent an organic pigment, carbon black and the like in place ofthe dye is taken into account. The pigment is insoluble in water.Thereby, the pigment can be used as an aqueous ink in which the pigmentis mixed and dispersed with a dispersing agent for stable dispersion inwater. Use of the pigment can bring about waterproof and lightresistance, but cannot meet other properties at the same time.Especially, the high-speed printing of the plain paper cannot obtainhigh image density and high coloring property, failing to sufficientlymeet the character feathering, the color bleeding, the both-sideprinting property and the like.

In the inkjet printing, a stable ejection of an ink droplet from a thinnozzle of an inkjet recording head is needed. For meeting the above, itis necessary that dryness of an orifice of the inkjet recording headdoes not cause solidification and the like of the ink. Use of adispersing agent-contained ink for the inkjet printing may sometimescause clogging or ink's ejection failure which may be attributable to aresin and the like (of the dispersing agent) that is not dissolved againafter adhering to the orifice and the like. Especially, a long-timestoppage of the printing is likely to cause the clogging of the nozzleand the like, moreover, the long-time stoppage may cause ink'saccumulation (the ink with increased viscosity) in a nozzle cap or in amaintenance mechanism such as intake-tube and the like, thus losingfunction of the maintenance mechanism. A temporary stoppage of printing,or a temporary stoppage of using a nozzle that corresponds to a blankeddocument or a blanked image may cause a printing failure and the likewhich may be attributable to disoriented direction of injection of inkdroplet (intermittent ejection failure). The above problems occurred sooften. An aqueous pigment ink containing the dispersing agent is viscousand causes a resistance in a path to a nozzle's head end in thelong-time continuous ejection and a high-speed printing, thus making theejection unstable and making it difficult to achieve a smooth printing.

For solving the above problems, the following inks are to be proposed.

Resin Dispersion Pigment Ink

For solving the above problems, Japanese Patent Application Laid-Open(JP-A) No. 2000-212486 discloses an ink having specific agents andproperty such as pigment, pigment density, water-soluble dispersingagent, and penetrating agent; an ink containing polyhydric alcoholalkylether derivatives; and an ink set thereof. The ink disclosed inJP-A No. 2000-212486 has a super permeability, and thereby has asufficient dryness even at a high-sped printing and has a securedejection stability. The ink disclosed in JP-A No. 2000-212486 is,however, inferior to a dye ink in terms of image density, colorreproducibility and the like when the plain paper is used. Although moreimproved in character feathering, color bleeding and both-side printingproperty than a conventional inkjet record image, a record imagedisclosed in JP-A No. 2000-212486 is inferior to a record image of anelectrophotographic method and the like used for plain paper printing onthe market, thereby is in need of more improvement.

Ink containing coloring agent-encapsulated resin dispersion Forimproving durability of the image, an ink is disclosed which contains acoloring agent-encapsulated resin dispersion which encapsulates acoloring agent in an insoluble-and-dispersing resin. However, the aboveink does not obtain a sufficient image density when a carbon black isused as the coloring agent. A color organic pigment used as the coloringagent for a conventional ink is inferior to a dye ink in terms of imagedensity, color reproducibility and the like on the plain paper. An inkset of the above coloring agent-encapsulated resin dispersion which setcombines a black ink with a color ink cannot bring about a sufficientcolor boundary bleeding between black and yellow.

Self-Dispersion Pigment Ink

Other dispersing methods include a self-dispersion pigment ink which iscapable of making a stable dispersion without a dispersing agent. Interms of a black pigment ink, JP-A No. 5-186704 and JP-A No. 8-3498disclose so-called a self-dispersion carbon black which is capable ofmaking a stable dispersion without a dispersing agent by introducing ahydrophilic group to a surface of carbon. Moreover, in terms of a colorpigment ink, JP-A No. 2000-513396 discloses a color pigment which iscapable of making a stable dispersion without a dispersing agent.

Combining the above self-dispersion pigment inks is low in terms ofchroma of a color image on plain paper, and deteriorated in terms offriction resistance on a special recording medium such as gloss paper.

Alternatively, JP-A No. 10-140064 discloses an ink set comprising ablack ink and a color ink in which a black ink having a self-dispersioncarbon black and a color ink containing a coloring material whosepolarity is opposite to that of a coloring material of the black ink.Furthermore, JP-A No. 2000-191972 discloses an ink set having coloringagent-encapsulated resin dispersion inks having different ionicities. Aprinted matter printed with the above ink sets are improved in terms ofcolor bleeding, however, still failing to meet other properties of theplain paper.

On the other hand, efforts for improving fitness to the pigment ink havebeen made with a coat paper type inkjet recording medium which isprovided with a coat layer on a base material. JP-A No.11-342669discloses the one having an ink accepting layer mainly composed ofwater-soluble resin. In JP-A No. 11-342669, an inkjet recording bodycontains hydroxy propyl methyl cellulose, moreover the ink acceptinglayer contains a single polymer resin (N-vinyl pyrrolidone) or acopolymer resin (N-vinyl pyrrolidone and other polymeric monomer). JP-ANo. 2000-108508 discloses an inkjet record sheet containing methoxylgroup-contained water-soluble cellulose derivative and water-solublecationic resin. JP-A No. 10-329405 discloses an inkjet record sheetwhich contains hydrophilic high molecular resin and a specific anionicfluorine surfactant.

As those having the ink accepting layer mainly composed of an inorganicpigment and binder resin, JP-A No. 10-119417 discloses an inkjet recordsheet provided with i) a base material sheet, ii) an ink permeationlayer (mainly composed of inorganic filler) disposed on the basematerial sheet, and iii) an ink swelling layer mainly composed ofwater-soluble resin. JP-A No. 10-329417 discloses an inkjet recordingfilm has a recording layer which is a sequential lamination of (A) anink accepting layer containing water-soluble resin, coarse face formingagent, and cross-linking agent, and (B) a layer containing dot-shaperegulating agent. In the above inkjet recording film, at least two typesof synthetic silicas having different oil-absorbing amount are used asthe coarse face forming agent. Varying the amount of use of these mayadjust the number of samplings of the recording layer in a range of 20to 100 and adjust an ink fixing period less than 5 minutes. JP-A No.11-99739 discloses an inkjet record sheet having a first ink acceptinglayer and a second ink accepting layer, in which the first ink acceptinglayer contains a resin component which is dissolved in or swelled with acoating solution for the second ink accepting layer. The second inkaccepting layer has pigment content more than that of the first inkaccepting layer. JP-A No. 11-245502 discloses an inkjet coating agentwhich contains a hydrophilic polyurethane and a silica mixture, wherethe hydrophilic polyurethane is contained in a range of 15% by weight to90% by weight relative to an entire coating agent, while the silicamixture (containing i. a silica having an average particle diameter 6 μmto 9 ρm is 10% by weight to 30% by weight, ii. a light diffusion silicahaving an average particle diameter 10 μm to 15 μm is 15% by weight to40% by weight, and iii. a porous silica having an average particlediameter 10 pm to 22 μm is 15% by weight to 40% by weight) is contained(solid content) in a range of 10% by weight to 80% relative to theentire coating agent.

JP-A No. 11-291619 discloses an inkjet recording film which is asequential lamination of an adhesive layer and an ink accepting layer,where the adhesive layer has main components including (A) a binder, (B)a coating film forming assistant, and (C) a cross-linking agent, and theinkaccepting layer has main components including a binder having thesame component as that of (A), (D) coarse face forming agent, across-linking agent having the same component as that of (C), and (E)catalyst, with the weight ratio of the binder to the coarse face formingagent 2:3 or 1:3. JP-A No. 11-301093 discloses an inkjet record materialhaving an ink solvent transmitting layer which transmits solvent on toan ink accepting layer but not transmit pigment. JP-A No. 2000-1043discloses an aqueous ink record material which is made from i)polyacetal resin,urea-glyoxal-acryl amide polycondensation product andepoxy compound, and resin composition composed of fine particle. JP-ANo. 2000-79752 discloses an inkjet recording body containing silica andthe like, and a cationic resin having cationic strength 1.5 mequivalent/g to 6 equivalent/g.

JP-A No. 2000-79752 and JP-A No. 2000-79754 disclose a record sheetwhich is partly deletable and which bears an inkjet printing pattern bymeans of a pigment ink which is incompatible with an ink acceptinglayer. JP-A No. 2000-127610 discloses an inkjet record sheet made from aporous starch particle and a binder resin, where an inorganic or organicparticle is embedded into the porous starch particle. JP-A No.2000-190622 discloses an inkjet record material formed of an inkaccepting layer which contains an inorganic pigment, a water-solubleresin, and a metal salt (which has ion valence of 2 or more). JP-A No.2000-238420 discloses an inkjet record sheet, where a pigment relativeto a binder agent is 100 weight part relative to a range of 10 weightpart 50 to weight part, a recording layer has main components includingi) a synthetic silica (as pigment) having average particle diameter 3 μmto 15 μm and ii) a polyvinyl alcohol having saponification 96 mol % ormore (binder agent), and quaternary ammonium salt polymer 1 weight partto 40 weight part relative to the pigment 100 weight part, and hardener20 weight part to 100 weight part relative to the binder agent 100weight part are contained.

JP-A No. 2000-247014 discloses an aqueous ink record material having, asmain component, polyvinyl acetal resin which is obtained by acetalizingpolyvinyl alcohol using aromatic aldehyde. In the polyvinyl acetalresin, a particle composed of at least one selected from thegroupconsisting of water-soluble acrylic resin, water-soluble epoxycompound, silic acid, silica, kaolin, clay, alumina, calcium carbonate,zeolite, titanium oxide, talc, and spherical high polymer. JP-A No.2000-318298 discloses an inkjet record sheet which has a lower layer(containing resin film, amorphous synthetic silica and water-insolubleresin), and an upper layer (containing amorphous synthetic silica,water-insoluble resin and silanol-modified polyvinyl alcohol), and whichhas smoothness 5 seconds to 40 seconds.

Moreover, in terms of aluminum oxide accepting layer, JP-A No.2000-37945 discloses an inkjet record sheet where an ink accepting layeris a fixed layer fixed by a binder which has, as main components, i)aluminum oxide fine particles (two different particle diameters) and ii)saponified polyvinyl alcohol (saponification 80 mol % to 95 mol %). JP-ANo.11-198520 discloses an inkjet record material which is a sequentiallamination of aluminum oxide layer (γ-type or δ-type), and a highmolecular-contained layer (water-soluble or water-swelled).

Any of the above publications fail to sufficiently meet the inkjet'sproperties such as ink absorption, image density, beading, fixingproperty (friction resistance), and the like.

Objects and Advantages

It is an object of the present invention to provide an inkjet recordingmethod and an inkjet recording apparatus which solve the aboveconventional shortcomings. Especially, it is the object of the presentinvention to provide the inkjet recording method and the inkjetrecording apparatus which are excellent in ejection stability and instorage stability, moreover, which can give the following images: i)having good color tone, ii) high image density, iii) high-sharpnessrecording image free from blur or feathering around character and image,iv) free from boundary color bleeding between different colors, v) freefrom unevenness, and vi) having rigidity such as waterproof,light-proof, and friction resistance.

Moreover, it is another object of the present invention to provide theinkjet recording method and the inkjet recording apparatus which canform high-quality and high rigidity image on various recording mediums.

After studying hard on the above problems, the present inventors havefound the following: An ink composed of specific agents (such as wettingagent, penetrating agent and water-soluble organic solvent) by using anemulsion containing a coloring material in a polymer fine particle islow in surface tension even though the above ink has higher viscositythan the conventional ink. With the above ink which has highpermeability, a vehicle may rapidly permeate in a high-speed printing ofplain paper, thereby coloring material composition is likely to remainon the surface. In spite of the above, the above ink can bring abouthigh chroma and high coloring density and bring about an image having aminute amount of strike-throughs.

Moreover, the present inventors have found the following. Combining thecolor ink (which contains a colored polymer fine particle and has theabove structure) with the black ink (which uses a self-dispersion carbonblack as a coloring material, and has high viscosity and low surfacetension like the color pigment ink) can bring about the followingeffects at high-speed plain paper printing: increasing image density ofblack, extremely reducing color bleedings between black and color, beingexcellent in coloring property, and obtaining a record image excellentin both-side printing property with a minute amount of strike-throughs.

Moreover, in view of the black ink (which contains the self dispersioncarbon black) and the color ink (which contains the colored polymer fineparticle), the present inventors have found the following: Varying thetypes of the recording medium and varying the ink type or ink ratioaccording to the printing mode can record on various recording mediumsan image that has high grade and excellent rigidity.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention, there is providedan inkjet recording apparatus, comprising: a black ink ejecting portionconfigured to eject a black ink containing a self-dispersion pigment;color ink ejecting portions configured to eject, respectively, a cyanink, a magenta ink and a yellow ink which comprise a polymer emulsionwhich comprises a polymer fine particle containing a coloring materialwhich is insoluble in water or slightly soluble in water; and arecording-controlling unit configured to control recording. The blackink ejecting portion and the color ink ejecting portion scan relative toa recording medium, to thereby record an image on the recording medium.When the recording medium is optically transparent and is provided, on atransparent-base material thereof, with an ink accepting layer, therecording-controlling unit controls recording on the recording mediumsuch that the color ink ejecting portion is used for recording amonochrome image and a color image which has a plurality of colors,leaving the black ink ejecting portion substantially free from beingused.

According to a second aspect of the present invention, there is providedan inkjet recording method, comprising: using an inkjet recordingapparatus which comprises: a black ink ejecting portion configured toeject a black ink containing a self-dispersion pigment; color inkejecting portions configured to eject, respectively, a cyan ink, amagenta ink and a yellow ink which comprise a polymer emulsion whichcomprises a polymer fine particle containing a coloring material whichis insoluble in water or slightly soluble in water; and arecording-controlling unit configured to control recording. The blackink ejecting portion and the color ink ejecting portion scan relative toa recording medium, to thereby record an image on the recording medium.When the recording medium is optically transparent and is provided, on atransparent base material thereof, with an ink accepting layer, therecording-controlling unit controls recording on the recording mediumsuch that the color ink ejecting portion is used for recording amonochrome image and a color image which has a plurality of colors,leaving the black ink ejecting portion substantially free from beingused. When the recording medium is optically transparent and isprovided, on the transparent base material thereof, with the inkaccepting layer, the inkjet recording method uses the color ink forrecording the monochrome image and the color image which has a pluralityof colors, leaving the black ink substantially free from being used.

According to a third aspect of the present invention, there is providedan inkjet recording apparatus, comprising: a black ink ejecting portionconfigured to eject a black ink containing a self-dispersion pigment;color ink ejecting portions configured to eject, respectively, a cyanink, a magenta ink and a yellow ink which comprise a polymer emulsionwhich comprises a polymer fine particle containing a coloring materialwhich is insoluble in water or slightly soluble in water; and arecording-controlling unit configured to control recording. The blackink ejecting portion and the color ink ejecting portion scan relative toa recording medium, to thereby record an image on the recording medium.When the recording medium is provided, on an opaque base materialthereof, with an ink accepting layer which has a surface having a gloss,the recording-controlling unit controls recording on the recordingmedium such that the color ink ejecting portion is used for recording amonochrome image and a color image which has a plurality of colors,leaving the black ink ejecting portion substantially free from beingused.

According to a fourth aspect of the present invention, there is providedan inkjet recording method using an inkjet recording apparatus whichcomprises: a black ink ejecting portion configured to eject a black inkcontaining a self-dispersion pigment; color ink ejecting portionsconfigured to eject, respectively, a cyan ink, a magenta ink and ayellow ink which comprise a polymer emulsion which comprises a polymerfine particle containing a coloring material which is insoluble in wateror slightly soluble in water; and a recording-controlling unitconfigured to control recording. The black ink ejecting portion and thecolor ink ejecting portion scan relative to a recording medium, tothereby record an image on the recording medium. When the recordingmedium is provided, on an opaque base material thereof, with an inkaccepting layer which has a surface having a gloss, therecording-controlling unit controls recording on the recording mediumsuch that the color ink ejecting portion is used for recording amonochrome image and a color image which has a plurality of colors,leaving the black ink ejecting portion substantially free from beingused. When the recording medium is provided, on the opaque base materialthereof, with the ink accepting layer which has the surface having thegloss, the inkjet recording method uses the color ink for recording themonochrome image and the color image which has a plurality of colors,leaving the black ink substantially free from being used.

According to a fifth aspect of the present invention, there is providedan inkjet recording apparatus, comprising: a black ink ejecting portionconfigured to eject a black ink containing a self-dispersion pigment;and color ink ejecting portions configured to eject, respectively, acyan ink, a magenta ink and a yellow ink which comprise a polymeremulsion which comprises a polymer fine particle containing a coloringmaterial which is insoluble in water or slightly soluble in water; and arecording-controlling unit configured to control recording. The blackink ejecting portion and the color ink ejecting portion scan relative toa recording medium, to thereby record an image on the recording medium.When a color image is recorded on a plain paper sheet and a black colorarea in the color image is recorded, the recording-controlling unitcontrols recording on the recording medium such that the black inkejecting portion and the color ink ejecting portion are used incombination.

According to a sixth aspect of the present invention, there is providedan inkjet recording method, comprising: using an inkjet recordingapparatus which comprises: a black ink ejecting portion configured toeject a black ink containing a self-dispersion pigment; and color inkejecting portions configured to eject, respectively, a cyan ink, amagenta ink and a yellow ink which comprise a polymer emulsion whichcomprises a polymer fine particle containing a coloring material whichis insoluble in water or slightly soluble in water; and arecording-controlling unit configured to control recording. The blackink ejecting portion and the color ink ejecting portion scan relative toa recording medium, to thereby record an image on the recording medium.

When a color image is recorded on a plain paper sheet and a black colorarea in the color image is recorded, the recording-controlling unitcontrols recording on the recording medium such that the black inkejecting portion and the color ink ejecting portion are used incombination. When the color image is recorded on the plain paper sheetand the black color area in the color image is recorded, the inkjetrecording method controls recording such that the black ink and thecolor ink are used in combination.

According to a seventh aspect of the present invention, there isprovided an inkjet recording apparatus, comprising: a black ink ejectingportion configured to eject a black ink containing a self-dispersionpigment; color ink ejecting portions configured to eject, respectively,a cyan ink, a magenta ink and a yellow ink which comprise a polymeremulsion which comprises a polymer fine particle containing a coloringmaterial which is insoluble in water or slightly soluble in water; and arecording-controlling unit configured to control recording. The blackink ejecting portion and the color ink ejecting portion scan relative toa recording medium, to thereby record an image on the recording medium.When the recording medium is provided, on an opaque base materialthereof, with an ink accepting layer which has a surface free from agloss and a black color area in the color image is recorded, therecording-controlling unit controls recording such that the black inkejecting portion and the color ink ejecting portion are used incombination.

According to an eighth aspect of the present invention there is providedan inkjet recording method using an inkjet recording apparatus whichcomprises: a black ink ejecting portion configured to eject a black inkcontaining a self-dispersion pigment; color ink ejecting portionsconfigured to eject, respectively, a cyan ink, a magenta ink and ayellow ink which comprise a polymer emulsion which comprises a polymerfine particle containing a coloring material which is insoluble in wateror slightly soluble in water; and a recording-controlling unitconfigured to control recording. The black ink ejecting portion and thecolor ink ejecting portion scan relative to a recording medium, tothereby record an image on the recording medium. When the recordingmedium is provided, on an opaque base material thereof, with an inkaccepting layer which has a surface free from a gloss and a black colorarea in the color image is recorded, the recording-controlling unitcontrols recording such that the black ink ejecting portion and thecolor ink ejecting portion are used in combination. When recording thecolor image on the recording medium which is provided, on the opaquebase material thereof, with the ink accepting layer which has thesurface free from the gloss, and when the black color area in the colorimage is recorded, the inkjet recording method controls recording suchthat the black ink and the color ink are used in combination.

According to a ninth aspect of the present invention, there is providedan inkjet recording apparatus, comprising: a black ink ejecting portionconfigured to eject a black ink containing a self-dispersion pigment;color ink ejecting portions configured to eject, respectively, a cyanink, a magenta ink and a yellow ink which comprise a polymer emulsionwhich comprises a polymer fine particle containing a coloring materialwhich is insoluble in water or slightly soluble in water; and arecording-controlling unit configured to control recording. The blackink ejecting portion and the color ink ejecting portion scan relative toa recording medium, to thereby record an image on the recording medium.When the recording is carried out on the recording medium which is in atleast one of the following cases: the recording medium is opticallytransparent and is provided, on a transparent base material thereof,with an ink accepting layer, and the recording medium is provided, on anopaque base material thereof, with an ink accepting layer which has asurface having a gloss, the recording-controlling unit controlsrecording on the recording medium such that the color ink ejectingportion is used for recording a monochrome image and a color image whichhas a plurality of colors, leaving the black ink ejecting portionsubstantially free from being used. When a black color area in the colorimage is recorded in at least one of the following cases: the colorimage is recorded on a plain paper sheet, and the color image isrecorded on the recording medium which is provided, on an opaque basematerial thereof, with an ink accepting layer which has a surface freefrom a gloss, the recording-controlling unit controls recording suchthat the black ink ejecting portion and the color ink ejecting portionare used in combination. In at least one of the following cases:recording the monochrome image on the plain paper sheet, and recordingthe monochrome image on the recording medium which is provided, on theopaque base material thereof, with the ink accepting layer which has thesurface free from the gloss, the recording-controlling unit controlsrecording such that the black ink ejecting portion is used, leaving thecolor ink ejecting portion substantially free from being used.

According to a tenth aspect of the present invention, there is providedan inkjet recording method using an inkjet recording apparatus whichcomprises: a black ink ejecting portion configured to eject a black inkcontaining a self-dispersion pigment; color ink ejecting portionsconfigured to eject, respectively, a cyan ink, a magenta ink and ayellow ink which comprise a polymer emulsion which comprises a polymerfine particle containing a coloring material which is insoluble in wateror slightly soluble in water; and a recording-controlling unitconfigured to control recording. The black ink ejecting portion and thecolor ink ejecting portion scan relative to a recording medium, tothereby record an image on the recording medium. When the recording iscarried out on the recording medium which is in at least one of thefollowing cases: the recording medium is optically transparent and isprovided, on a transparent base material thereof, with an ink acceptinglayer, and the recording medium is provided, on an opaque base materialthereof, with an ink accepting layer which has a surface having a gloss,the recording-controlling unit controls recording on the recordingmedium such that the color ink ejecting portion is used for recording amonochrome image and a color image which has a plurality of colors,leaving the black ink ejecting portion substantially free from beingused. When a black color area in the color image is recorded in at leastone of the following cases: the color image is recorded on a plain papersheet, and the color image is recorded on the recording medium which isprovided, on an opaque base material thereof, with an ink acceptinglayer which has a surface free from a gloss, the recording-controllingunit controls recording such that the black ink ejecting portion and thecolor ink ejecting portion are used in combination. In at least one ofthe following cases: recording the monochrome image on the plain papersheet, and recording the monochrome image on the recording medium whichis provided, on the opaque base material thereof, with the ink acceptinglayer which has the surface free from the gloss, therecording-controlling unit controls recording such that the black inkejecting portion is used, leaving the color ink ejecting portionsubstantially free from being used. In at least one of the followingcases: the recording medium is optically transparent and is provided, onthe transparent base material thereof, with the ink accepting layer, andthe recording medium is provided, on the opaque base material thereof,with the ink accepting layer which has the surface having the gloss, theinkjet recording method controls recording on the recording medium suchthat the color ink is used for recording the monochrome image and thecolor image which has a plurality of colors, leaving the black inksubstantially free from being used. When the black color area in thecolor image is recorded in at least one of the following cases: thecolor image is recorded on the plain paper sheet, and the color image isrecorded on the recording medium which is provided, on the opaque basematerial thereof, with the ink accepting layer which has the surfacefree from the gloss, the inkjet recording method controls recording suchthat the black ink and the color ink are used in combination. In thefollowing case: recording the monochrome image, the inkjet recordingmethod controls recording such that the black ink is used, leaving thecolor ink substantially free from being used.

According to an eleventh aspect of the present invention, there isprovided an inkjet recording apparatus, comprising: a black ink ejectingportion configured to eject a black ink containing a self-dispersionpigment, and a polymer emulsion as a fixing agent; color ink ejectingportions configured to eject, respectively, a cyan ink, a magenta inkand a yellow ink which comprise a polymer emulsion which comprises apolymer fine particle containing a coloring material which is insolublein water or slightly soluble in water; and a recording-controlling unitconfigured to control recording. The black ink ejecting portion and thecolor ink ejecting portion scan relative to a recording medium, tothereby record an image on the recording medium. When a black color areain the color image is recorded in any one of the following cases: i) therecording medium is optically transparent and is provided, on atransparent base material thereof, with an ink accepting layer, ii) therecording medium is provided, on an opaque base material thereof, withan ink accepting layer which has a surface having a gloss, iii) a colorimage is recorded on a plain paper sheet, and iv) the recording mediumfor recording the color image is provided, on an opaque base materialthereof, with an ink accepting layer which has a surface free from agloss, the recording-controlling unit controls recording such that theblack ink ejecting portion and the color ink ejecting portion are usedin combination.

According to a twelfth aspect of the present invention, there isprovided an inkjet recording method using an inkjet recording apparatuswhich comprises: a black ink ejecting portion configured to eject ablack ink containing a self-dispersion pigment, and a polymer emulsionas a fixing agent; color ink ejecting portions configured to eject,respectively, a cyan ink, a magenta ink and a yellow ink which comprisea polymer emulsion which comprises a polymer fine particle containing acoloring material which is insoluble in water or slightly soluble inwater; and a recording-controlling unit configured to control recording.The black ink ejecting portion and the color ink ejecting portion scanrelative to a recording medium, to thereby record an image on therecording medium. When a black color area in the color image is recordedin any one of the following cases: i) the recording medium is opticallytransparent and is provided, on a transparent base material thereof,with an ink accepting layer, ii) the recording medium is provided, on anopaque base material thereof, with an ink accepting layer which has asurface having a gloss, iii) a color image is recorded on a plain papersheet, and iv) the recording medium for recording the color image isprovided, on an opaque base material thereof, with an ink acceptinglayer which has a surface free from a gloss, the recording-controllingunit controls recording such that the black ink ejecting portion and thecolor ink ejecting portion are used in combination. When the black colorarea in the color image is recorded in any one of the following cases:i) the recording medium is optically transparent and is provided, on thetransparent base material thereof, with the ink accepting layer, ii) therecording medium is provided, on the opaque base material thereof, withthe ink accepting layer which has the surface having the gloss, iii) thecolor image is recorded on the plain paper sheet, and iv) the recordingmedium for recording the color image is provided, on the opaque basematerial thereof, with the ink accepting layer which has the surfacefree from the gloss, the inkjet recording method controls recording suchthat the black ink ejecting portion and the color ink ejecting portionare used in combination.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic front view of a mechanism part of a serial inkjetrecording apparatus of the present invention which incorporates thereinan ink cartridge receiving therein a recording liquid.

FIG. 2 is an external perspective view of the ink cartridge before beingincorporated into the recording apparatus of the present invention.

FIG. 3 is a cross section of the ink cartridge of the present invention.

FIG. 4 is an external perspective view of a record unit which isintegrated with a recording head of the present invention.

FIG. 5 is an external perspective view of another example of the inkcartridge of the present invention.

FIG. 6 is a schematic of another example of the inkjet recordingapparatus of the present invention having the ink cartridge housingtherein the recording liquid.

FIG. 7 is a block diagram showing a structure of a print systemaccording to a first embodiment of the present invention.

FIG. 8 is a block diagram showing a structure of a color-modifyingmodule of the present invention.

FIG. 9 is a block diagram showing another structure of thecolor-modifying module of the present invention.

FIGS. 10A and 10B are line maps for explaining BG/UCR proceduraltreatment for character part and line image part in a BG/UCR treatingsection in FIG. 9.

FIGS. 11A and 11B are line maps for explaining BG/UCR proceduraltreatment for photograph part in the BG/UCR treating section in FIG. 9.

FIG. 12 is a block diagram showing another structural example ofcolor-modifying module of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter described referring to drawings is a recording liquidcartridge receiving therein a recording liquid and an inkjet recordingapparatus equipped with the recording liquid cartridge, of the presentinvention. Of the present invention, structural examples shown beloware, however, not limited thereto.

FIG. 1 is a schematic front view of a mechanism part of a serial inkjetrecording apparatus which incorporates therein an ink cartridge equippedwith a recording liquid receiver receiving therein a recording liquid,of the present invention.

The mechanism part of the inkjet recording apparatus has the followingstructure: Between a side plate (1) and a side plate (2), a main guiderod (3) and a follower guide rod (4) are suspended substantiallyhorizontally. By means of the main guide rod (3) and the follower guiderod (4), a carriage unit (5) is born in such a manner as to slide in amain scanning direction. The carriage unit (5) incorporates therein fourinkjet heads (6) respectively ejecting a yellow ink (Y), a magenta ink(M), a cyan ink (C), and a black ink (Bk), with ejection faces (6 a)(nozzle face) thereof turning downward. On an upper side of the inkjetheads (6) of the carriage unit (5), four ink cartridges ((7 y), (7 m),(7 c), (7 k)) are replaceably installed which supply respective colorsto the four inkjet heads (6).

The carriage unit (5) has such a structure where driving and controllinga main scanning motor (8) connected to a timing belt (11) tensed betweena driving pulley (driving timing pulley) (9) (which is rotated with themain scanning motor (8)) and a follower pulley (idler pulley) (10) canmove the carriage unit (5) and the four inkjet heads (6) in the mainscanning direction.

A sub-frame (13) and a sub-frame (14) stand on a base plate (12)connecting the side plate (1) and the side plate (2). Between thesub-frame (13) and the sub-frame (14), a conveyer roller (15) isrotatably born for conveying a paper sheet (16) in a sub-scanningdirection perpendicular to the main scanning direction. A sub-scanningmotor (17) is disposed beside the sub-frame (14). For conveying arotation of the sub-scanning motor (17) to the conveyer motor (15),there are provided a gear (18) fixed to a rotary shaft of thesub-scanning motor (17) and a gear (19) fixed to a shaft of the conveyerroller (15).

Moreover, between the side plate (1) and the sub-frame (12), there isprovided a reliability maintaining-recovering mechanism (hereinafterreferred to as “sub system”) (21) of the inkjet head (6). A holder (23)holds four cap members (22) for respectively capping the ejection facesof the inkjet heads (6). The holder (23) is swingably held with a linkmember (24). Moving the carriage unit (5) in the main scanning directionsuch that the carriage unit (5) abuts on an engagement portion (25)disposed on the holder (23) can lift the holder (23) in accordance withthe movement of the carriage unit (5), thereby the cap members (22) maycap the ejection faces (6 a) of the inkjet heads (6). On the contrary,moving the carriage unit (5) to a printing area side may lower theholder (23) in accordance with the movement of the carriage unit (5),thereby the cap members (22) may be spaced apart from the ejection faces(6 a) of the inkjet heads (6).

Each of the cap members (22) connects to an absorption pump (27) by wayof an absorption tube (26). Moreover, the cap member (22) formed with anatmospheric opening communicates to an atmosphere by way of anatmospheric opening tube and an atmospheric opening valve. Moreover, awaste liquid pumped by the absorption pump (27) is drained to a wasteliquid preservation tank (not shown) by way of a drain tube and thelike. On a side of the holder (23), a wiper blade (28) is mounted to ablade arm (29). The wiper blade (28) is a wiping member made of anelastic material such as fiber member, bubbling member, rubber, and thelike. The blade arm (29) is so born as to be swingable with a cam whichis rotated by means of a driving member (not shown).

Described next referring to FIG. 2 and FIG. 3 is the ink cartridge (7).

FIG. 2 is an external perspective view of the ink cartridge before beingincorporated into the printer of the present invention. FIG. 3 is across section of the ink cartridge of the present invention.

As is seen in FIG. 3, the ink cartridge (7) has a cartridge body (41)receiving therein an ink absorbent (42) absorbing therein the in ofspecific color. The cartridge body (41) is so formed that an upper covermember (44) is adhered or welded to an upper opening of a case (43), andis a mold which is made, for example, by resin. The ink absorbent (42)is made of porous body such as urethane foam and the like. After beingcompressively inserted in the cartridge body (41), the ink absorbent(42) may absorb the ink.

The case (43) of the cartridge body (41) has a base portion which isformed with an ink supply port (45) for feeding the ink to the recordinghead (6). The ink supply port (45) has an inner periphery to mating witha seal ring (46). The upper cover member (44) is formed with anatmospheric opening (47).

A cap member (50) is mounted to the cartridge body (41). The cap member(50) may prevent leak of the inside ink which leak may be caused by acompressive deformation of the case (43) in the following state: i)before loading and when the ink supply port (45) is blocked, handlingthe ink cartridge (7) for loading or transportation, or ii) when apressure is applied to a wide sidewall during vacuum packing.

As is seen in FIG. 2, the atmospheric opening (47) is sealed by sealingto the upper cover member (44) a film-shaped seal member (55) which hasoxygen permeability of 100 ml/m² or more. The seal member (55) has sucha dimension as to seal the atmospheric opening (47) and a plurality ofgrooves (48) which are formed around the atmospheric opening (47).Sealing the atmospheric opening (47) with the seal member (55) havingthe oxygen permeability of 100 ml/m² or more may bring about thefollowing effect:

Effect)

Even in the following state i), with the cartridge (7) packed under adecreased pressure using a pack member made of an aluminum laminate filmand the like that is free from air permeability, and with the ink beingloaded:

-   -   state i) an atmosphere present in a space (A) (see FIG. 3) that        is formed between the ink absorbent (42) and the cartridge body        (41) causes air to be dissolved in the ink;    -   the air in the ink can be exhausted via the seal member (55) to        a space (between the cartridge body (41) and the pack member        which is disposed outside the cartridge body (41)) having a high        degree of vacuum, thus improving degassing of the ink.

FIG. 4 shows a structural example of a record cartridge which isprovided with an ink receiver (receiving therein the recording liquid)and a head portion for ejecting the recording liquid.

Specifically, a record unit (30) is of a serial type, which includesmain elements such as an inkjet head (6), an ink tank (41) for receivingtherein the recording liquid fed to the inkjet head (6), and a covermember for sealing an inner part of the ink tank (41). The ink head (33)is formed with a plurality of nozzles (32) for ejecting the recordingliquid. The ink (recording liquid) is led to a common liquid chamber(not shown) by way of an ink supply tube (not shown), and is to beejected from the nozzle (32) in accordance with an electric signal froma record device body which signal is inputted from an electrode (31).The record unit of the above type is referred to as so-called thermaltype or bubble type which can be produced at low cost due to itsstructure, namely, a structure suitable for the head that has itsdriving source of thermal energy. The recording liquid of the presentinvention, with at least one of polyol having 8 to 11 carbon atoms andglycol ether having 8 to 11 carbon atoms added thereto in the printingmethod such as the above bubble type, thermal type and the like, canimprove wetting property to a thermal element. With this, even a smallamount of addition of the above components can bring about the ejectionstability and frequency stability, and increase safety, which ispreferable.

FIG. 5 shows an external perspective view of the ink cartridge,according to another example.

In an ink cartridge (1) in FIG. 5, an ink bag (2) is cased in a casebody (3). The case body (3) is composed of a first structural member(11), a second structural member (12) and a third structural member (13)which are so structured as to be secured by a screw member (82). Withthe above structure, the ink cartridge (1) can be prevented from beingnaturally decomposed when the ink cartridge (1) is mounted to ordismounted from the recording apparatus body.

The ink cartridge (1) in FIG. 5 is provided with an ink supply port(25), an opening portion (53) for the ink supply port (25), a dentportion (41) for mounting the ink cartridge (1) to the recordingapparatus body and dismounting the ink cartridge (1) from the recordingapparatus body, a hook portion (42), a guide portion (44), and a guideportion (45). Moreover, the ink cartridge (1) is provided with a coloridentifying unit (64) for presenting the ink color.

Hereinafter described referring to FIG. 6 is an example of the inkjetrecording apparatus using the ink cartridge (1). FIG. 6 is a schematicfor explaining an entire structure of the mechanism part of the inkjetrecording apparatus.

The inkjet recording apparatus is provided with an apparatus body 101, apaper supply tray 102 installed to the apparatus body 101 and loadedwith a paper sheet, a paper ejecting tray 103 installed to the apparatusbody 101 and stocking the paper sheet where the image is recorded(formed). An upper cover 111 of the apparatus body 101 has substantiallya flat upper face, and a front cover face 112 of the apparatus body 101is inclined backward relative to the flat upper face of the upper cover111. Below the inclined front cover face 112, there are provided thepaper ejecting tray 103 and the paper supply tray 102 which protrudeforward (near side).

In the apparatus body 101, as is seen in FIG. 6, by means of a guide rod131 and a stay 132, a carriage 133 is held in such a manner as to slidein the main scanning direction, where the guide rod 131 is a guidemember which is laterally suspended to a right plate (not shown) and aleft plate (not shown). With the above structure, a main scanning motor(not shown) may move the carriage 133 for scanning.

The carriage 133 is provided with a recording head 134 having fourinkjet heads for ejecting respective four ink droplets including yellow(Y), cyan (C), magenta (M) and black (Bk). Hereinabove, a plurality ofink ejection ports of the recording head 134 are arranged in a directionintersecting with the main scanning direction. The recording head 134defines an ink droplet ejecting direction turning downward.

Examples of the inkjet head constituting the recording head 134 includethe one having the following actuators and the like as energy generatingunit for ejecting the ink: a piezoelectric actuator such aspiezoelectric element, a thermal actuator using phase variationattributable to film boiling of the liquid by using electric heatexchanger element such as exothermic resistor, a shape-memorizing alloyactuator using metal phase variation attributable to temperature change,and an electrostatic actuator using electrostatic force.

The carriage 133 is provided with subtanks 135 for supplying variouscolor inks to the recording head 134. By way of an ink supply tube (notshown), the ink can be supplied to the subtank 135 from the inkcartridge 1 (mounted to an ink cartridge mounting portion) of thepresent invention.

On the other hand, as a paper feeding portion for feeding a paper sheet142 loaded on a paper loading portion 141 (pressure plate) of the papersupply tray 103, there is provided a separating pad 144 which is opposedto a lunula roll 143 (paper feed roll), and which is made of materialhaving a large friction coefficient, where the lunula roll 143 separatesthe paper sheet 142 one-by-one and conveys the thus separated papersheet 142 from the paper loading section 141. The separating pad 144 isbiased to the paper feed roll 143's side.

As a conveying portion for conveying below the recording head 134 thethus supplied paper sheet 142 from the paper supply portion, there areprovided i) a conveyor belt 151 for electrostatically absorbing thepaper sheet 142 and conveying the paper sheet 142, ii) a counter roller152 for conveying the paper sheet 142 (conveyed from the paper supplyportion via a guide 145) by interposing the paper sheet 142 between theconveyor belt 151 and the counter roller 152, iii) a conveyor guide 153for turning the paper sheet 142 (which is conveyed substantiallyvertically upward) by about 90°, to thereby smoothly put the paper sheet142 on the conveyor belt 151, and iv) and an end pressuring roll 155biased toward the conveyor belt 151's side by means of a pressing member154. Moreover, there is provided a charging roller 156 which is acharging unit for charging a surface of the conveyor belt 151.

Herein, the conveyor belt 151 is an endless belt which is bridgedbetween a conveyor belt 157 and a tension roller 158, to thereby havesuch a structure to as rotate in the belt conveying direction. Theconveyor belt 151 is made from a pure resin which is not subjected toresistance control and has thickness about 40 μm. The conveyor belt 151has i) a surface layer for paper absorbing face which is made from, forexample, ETFE pure material, and ii) a back layer (intermediaryresistance layer, earth layer) which has the same material as that forthe surface layer and is subjected to the resistance control.

The conveyor belt 151 has a backside where a guide member 161 is locatedcorresponding to a printing-photographing area defined by the recordinghead 134.

As a paper ejecting portion for ejecting the paper sheet 142 recorded bythe recording head 134, there are provided a separating claw 171 forseparating the paper sheet 142 from the conveyor belt 151, a paperejecting roller 172, a paper ejecting roll 173, and the paper ejectingtray 103 below the ejecting roller 172.

On a backface of the apparatus body 101, a both-face paper supply unit181 is detachably mounted. The both-face paper supply unit 181 takestherein the paper sheet 142 returned in an opposite rotary direction ofthe conveyor belt 151, and reverses the thus taken paper sheet 142 tothereby supply the paper sheet 142 again to between the counter roller152 and the conveyor belt 151. The both-face paper supply unit 181 hasan upper face provided with a manual paper feed portion 182.

With the above structure of the inkjet recording apparatus, the papersheet 142 may be separated one by one and supplied from the paper supplyportion substantially vertically upward, and then be guided by the guide145, and then be interposed between the conveyor belt 151 and thecounter roller 152. Then, with the end of the paper sheet 142 guided bythe conveyor guide 153, the paper sheet 142 may be pressed on to theconveyor belt 151 by means of the end pressing roll 155 for turning byabout 90°.

Hereinabove, the conveyor belt 157 is charged by the charging roller156, and the paper sheet 142 is electrostatically absorbed to theconveyor belt 151 for conveyance. Moving the carriage 133 while drivingthe recording head 134 corresponding to an image signal can make arecording of 1 line by ejecting the ink droplet to the stationary papersheet 142. Then, after the paper sheet 142 is conveyed by apredetermined amount, the next line recording is to be carried out. Witha recoding end signal received or a signal signifying that the back endof the paper sheet 142 reached the recording area received, therecording operation is to be ended, to thereby eject the paper sheet 142to the paper ejecting tray 103.

When it is sensed that the ink remnant comes to “near end” in thesubtank 135, a predetermined amount of ink is to be supplied to thesubtank 135 from the ink cartridge 1.

With the inkjet recording apparatus having the ink cartridge 1 of thepresent invention, when the ink cartridge 1 is used up, replacing onlythe ink bag 2 is possible by disassembling the case body 3. Even whenthe ink cartridge 1 is put longitudinally and loaded on the front face,the ink can be supplied stably. With this, even when the apparatus body101 has a blocked upper portion (for example, the ink cartridge 1 isreceived in a rack, or when an object is put on the upper face of theapparatus body 101), replacing the ink cartridge 1 is accomplished withease.

Hereinabove described is the serial inkjet recording apparatus. Therecording liquid of the present invention may also be applied toso-called a line head recording apparatus where the nozzles arearbitrarily arranged in a form of a zigzag, and the density is such thatit is substantially the same as the target image resolution or severalfractions of the target image resolution, to be arranged with therecording medium's width or more.

Examples of the recording apparatus hereinabove include PC (hostcomputer) and an output print for digital camera. In addition, examplesof the recording apparatus hereinabove include an apparatus ofcomplicated functions such as fax, scanner, telephone and the like.

When being used as the output printer of the PC, the inkjet recordingapparatus is to be connected to the PC via a cable and controlled bymeans of a driver software installed in the PC.

The following Table 1 and Table 2 show the way of recording by using theinks to be selected according to the types of the recording medium,under the present invention. In the Table 1 and the Table 2, C denotescyan ink, M denotes magenta ink, Y denotes yellow ink and K denotesblack ink. TABLE 1 (When black ink does not contain resin emulsion)Recording medium Color mode Monochrome mode OHP sheet Three-color (CMY)Three-color (CMY) recording recording (K) not used (K) not used Glosspaper Three-color (CMY) Three-color (CMY) recording recording (K) notused (K) not used Plain paper Four-color (CMYK) One-color (K) recording,or recording four-color (CMYK) recording Mat coat paper Four-color(CMYK) One-color (K) recording, or recording four-color (CMYK) recording

TABLE 2 (When black ink contains resin emulsion) Recording medium Colormode Monochrome mode OHP sheet Four-color (CMYK) One-color (K)recording, or recording four-color (CMYK) recording Gloss paperFour-color (CMYK) One-color (K) recording, or recording four-color(CMYK) recording Plain paper Four-color (CMYK) One-color (K) recording,or recording four-color (CMYK) recording Mat coat paper Four-color(CMYK) One-color (K) recording, or recording four-color (CMYK) recording

When the self-dispersion black ink does not contain the resin emulsion,for the recording medium (such as OHP sheet and gloss paper) having finepore in the ink accepting layer surface, the black ink is substantiallynot used mainly due to deteriorated friction resistance. When theself-dispersion black ink contains the resin emulsion, the black ink isused due to improved friction resistance even to the OHP sheet and thegloss paper.

Hereinafter described is each mode of the present invention.

When the recording medium is provided, on a transparent base materialthereof, with the ink accepting layer (namely, the recording medium isthe OHP sheet and the like), the three color inks CMY are to be used forthe color mode. The black part can be formed by overlapping the C, M andY, which is what is called a composite black. The above formation of theblack part is for the following reason: When the ink accepting layer ofthe recording medium has its main component of resin, recording theblack part using the self-dispersion black ink may crack the recordingpart. When the ink accepting layer of the recording medium is made oftransparent porous layer made of inorganic fine particles, the recordimage may lack friction resistance and thereby be peeled off with ease.The pigment of the self-dispersion black ink having large particlediameter cannot permeate into the ink accepting layer, and thereby mayremain on the surface. Moreover, the pigment of the self-dispersionblack ink does not contain a component that acts as binder. The colorinks CMY also have pigment as coloring agent. The color inks CMY can,however, bring about a record image that is excellent in frictionresistance for the following reason: The vinyl polymer, the polyesterpolymer, the polyurethane polymer and the like, which are used as apolymer forming the polymer emulsion, have high compatibility with theink accepting layer, sufficiently accomplishing an effect as binder ofthe coloring agent.

For the same reason, in the case of the monochrome mode, the recordingis to be carried out with the three colors CMY, namely, so-called thecomposite black.

When a recording medium is provided, on an opaque base material thereof,with an ink accepting layer having a surface having a gloss (namely, inthe case of gloss paper and the like), the color mode and the monochromemode are to be recorded with the tree color inks CMY, for the reasonsdescribed in the above OHP sheet's case.

When the recording medium is plain paper, the color mode is to berecorded with four color inks CMYK. The plain paper is not provided withthe ink accepting layer, has a rough surface of the recording medium,and has larger irregularity than the OHP sheet and the gloss paper. Withthe above features of the plain paper, even when the black part isrecorded using the self-dispersion black ink, the pigment may beprotected by the protrusion on the surface, securing friction resistanceof the record image. In the case of the monochrome mode, the black inkonly is to be used for the recording. Of the present invention, theplain paper is the one generally used at the office and is not providedwith the ink accepting layer.

When the recording medium is provided, on the opaque base materialthereof, with the ink accepting layer having the surface free from thegloss, like the case of the plain paper, the color mode is to berecorded with the four inks CMYK. On the other hand is this case, forthe monochrome mode, the black ink alone is to be used for therecording. A mat coat which is referred to as a special paper sheet forthe inkjet has comparatively a large irregularity, although not as largeas that of the plain paper. Therefore, when the black part of the matcoat paper is recorded using the self-dispersion black ink, the pigmentmay be protected by the protrusion on the surface, securing frictionresistance of the record image.

FIG. 7 is a block diagram showing an example of the system of the inkjetrecording apparatus of the present invention.

The print system has a host computer 101 and a printer 102, where thehost computer 101 transforms document data composed of a character part,a line drawing part, and a photograph part, and the printer 102 mayconvert a drawing command row from the host computer 101 into a bitmapimage.

The host computer 101 has a controlling portion 110 realized by amicrocomputer inducing CPU, ROM, RAM and the like. The controllingportion 110 may carry out an application software 111, to therebydevelop an electronic document 112 (document data) composed of thecharacter part, the line drawing part, and the photograph part. Thedocument data 112 is to be converted into a print data (PDL) which isthe drawing command row interpreted by the printer 102 with a printerdriver software 113, thereby to be transferred to the printer 102.

The printer 102 is a printing apparatus (that is capable of printing acolor) such as a color laser printer and the like. A printer controller120 realized by the microcomputer including the CPU, the ROM, the RAMand the like may read the print data 114 transferred from the hostcomputer 101 to an input buffer 121.

The printer controller 120 may interpret the drawing command row of theprint data 114 stored in the input buffer 121. When the thus interpreteddrawing command row is color information, a color converting module 122may carry out i) a procedural treatment (generating black color(BG)/removing under color (UCR) and ii) a controlling treatment (namely,controlling an in-printing ink's total amount), to thereby convert thedrawing command row into CMYK value.

In the case of the drawing information, a bitmap generating module 123may develop a drawing pattern on a bitmap memory 124 in accordance withthe CMYK value determined by the color converting module 122. When thedrawing command is a print start command, the bitmap image which was sofar developed on the bitmap memory 124 may be printed on the recordpaper with an engine (inkjet head portion) 125.

Hereinafter described is the color converting module 122 of the presentinvention. FIG. 8 shows a general color converting module, according tothe conventional technology. A BG/UCR treating portion 130 may subjectan input RGB to a BG/UCR procedural treatment, to thereby convert theinput RGB into CMYK. In the case of the character part and the linedrawing part, the input RGB hereinabove signifies color density. In thecase of the photography part, the input RGB signifies density of eachpixel.

Moreover, when the total of the CMYK is over a predetermined value, atotal amount controlling-treating portion 131 may correct the totalCMYK's value within the predetermined value, and finally y conversion isto be carried out with a γ table 132. The total amountcontrolling-treating portion 131 and the γ table 132 table arereversible.

The printer controller 120 and the color converting module 122 subjectthe character part, the line drawing part and the photograph part of thedrawing command row of the document data to respectively different blackgenerating procedural treatments and respectively different under colorremoval procedural treatments, followed by bit-imaging.

Moreover, the total amount controlling-treating portion 131 subject thecharacter part, the line drawing part and the photograph part of thedrawing command row of the document data to controls of respectivelydifferent in-printing ink's total amounts.

The host computer 101 of the print system may convert the document datainto the drawing command row, and the printer 102 of the print systemmay carry out different BG/UCR procedural treatments respectively forthe character part, the line drawing part and the photograph part of thedrawing command row, followed by the bitmap imaging. Then, the printingis to be carried out on the data record paper which is subjected to thebitmap imaging.

In the printer 102, the character part, the line drawing part and thephotograph part of the drawing command row are to be subjected todifferent in-printing ink' amount controls respectively.

FIG. 9 shows a block diagram of another structure of the colorconverting module 122 in FIG. 7. The color converting module 122 in FIG.9 has the following difference from the conventional color convertingmodule in FIG. 6: To signify for which part (among the character part,the line drawing part and the photograph part) the RGB value is used,the color converting module 122 in FIG. 9 inputs tag information (Tag)to a BG/UCR treating portion 140, together with the input RGBinformation.

The print system of this embodiment uses the PDL type printer 102 thatcarries out the bitmapping of the document data on the printercontroller 120's side, thereby assuredly distinguishing whether thedrawing pattern is the character part, the line drawing part or thephotograph part.

The BG/UCR treating portion 140 subjects the character part, the linedrawing part and the photograph part of the drawing command row torespectively different black generating procedural treatments andrespectively different under color removal procedural treatments. In thetreatments, the color character and the colored line put emphasis onsharpness than gradation, while the photograph part puts emphasis ongradation and hue.

FIG. 10A and 10B show line drawings for explaining the BG/UCR proceduraltreatments for the character part and the line drawing part in theBG/UCR treating portion 140. As is seen respectively in FIG. 10B andFIG. 10A, 100% BG procedural treatment and 100% UCR procedural treatmentare to be carried out, where a minimum density contest is to be deductedfrom all colors by cyan density, magenta density and yellow density, andthe thus deducted amount is to be replaced with black. In this case, theink's total adhesion amount is decreased, thereby sharpening thedocument data as a whole.

In the above manner, the BG/UCR procedural treatment can be carried outwithout decreasing the gradation of the photograph part of the documentdata or without damaging sharpness of the character part.

FIGS. 11A and 11B show line drawings for explaining the BG/UCRprocedural treatments for the photograph part in the BG/UCR treatingportion 140. As is seen respectively in FIG. 11B and FIG. 11A, thephotograph part puts emphases on the gradation and hue, to thereby carryout the BG procedural treatment and the UCR procedural treatment. Withthis, the BG procedural treatment and the UCR procedural treatment areto be carried out within such an extent that the “color boundarybleeding,” “beading,” “drying failure” and “back-through” are not causedby the total adhesion amount.

The description is to be made in the case that the recording is carriedout on an optically transparent recording medium which is provided, on atransparent base material thereof, with an ink accepting layer andcarried out on a recording medium which is provided, on an opaquematerial thereof, with an ink accepting layer having a gloss. Whenrecoding the monochrome image or the color image (which has a pluralityof colors), the recording is carried out with the color ink only,substantially without the black ink. Therefore, the BG and the UCR areeach preferred to be 10% or less, and more preferably 0%.

A total amount controlling-treating portion 141 in FIG. 9 controlsrespectively different ink's total amounts of the character part, theline drawing part and the photograph part. The above BG/UCR proceduraltreatment can decrease the ink's adhesion amount. This decreasing is,however, not accomplished when the input is the CMYK or a secondarycolor. Therefore, for suppressing the ink's bleeding, the total amountcontrol is to be carried out on the CMYK value that is subjected to theBG/UCR procedural treatment.

In general, the ink's bleeding may easily be caused to the characteredge, the thin line edge and the like. In terms of this, for input tothe total amount controlling-treating portion 141, decreasing the ink'stotal amount in the case of the character part and the line drawing partcan suppress the ink's bleeding of the character part and the linedrawing part without damaging the gradation and the hue of thephotograph part. Then, finally, the γ conversion is to be carried outwith a γ table 142.

In the above manner, the ink's total amount can be suppressed withoutdecreasing the gradation of the photograph part of the document data ordamaging the sharpness of the character part of the document data.

Then, the ink's bleeding may be dependent on the printer 102'smachine-to-machine difference, record paper, and the print outputenvironment. In terms of this, providing a unit for inputting fineadjustment amount relative to the standard total control amount which isdesignated by an operation portion (not shown) of the printer 102 or bythe printer deriver software 113 can absorb variation attributable tothe machine-to-machine difference and the output environment.

FIG. 12 shows a block diagram of still another structure of the colorconverting module 122 in FIG. 7 of the present invention. A total amountcontrol fine adjustment value 144 of each of the respective characterpart, line drawing part and photograph part inputted from an input unit143 is to be set at the total amount controlling-treating portion 141.The input unit 143 is operated by i) the operation portion of theprinter 102 or by ii) a printer driver which is realized by the printercontroller 120 carrying out the printer driver software 113.

In the above print system, the input unit 143 operated by the operationportion or the printer driver can input to the total amountcontrolling-treating portion 141 the total amount control fineadjustment value 144 of the in-printing inks adaptable respectively tothe character part, the line drawing part, and the photograph part ofthe drawing command row of the document data.

Namely, the input unit 143 inputs the fine adjustment value of thein-printing ink's total amounts adaptable respectively to the characterpart, the line drawing part, and the photograph part of the drawingcommand row of the document data.

In the above manner, for each of the character part, the line drawingpart, and the photograph part of the document data, the ink's totalamount control values can be adjusted to the optimum value according tothe printing environment.

When interpreting the input data in the printing, the print systemaccording to this embodiment carries out the BG/UCR procedural treatmentafter the tag information (whether the drawing pattern is the characterpart, the line drawing part or the photograph part) is determined,thereby enabling procedural treatments of the respective character part,line drawing part and photograph part of the data. With this, thegradation of the photograph part is not decreased, while the sharpnessof the character part can be kept.

When interpreting the input data in the printing, the print systemaccording to this embodiment carries out the ink's total amountcontrolling treatment after the tag information (whether the drawingpattern is the character part, the line drawing part or the photographpart) is determined, thereby enabling the total amount controls whichare different respectively with the character part, the line drawingpart and the photograph part of the document data.

When interpreting the input data in the printing, the print systemaccording to this embodiment can adjust the ink's total control amountsof the respective character part, line drawing part and photograph part.

Described in the above embodiment is the print system, however, theprinting apparatus having a combined function of the host computer 101and the printer 102 can be used likewise.

In the above case, when the controlling portion and the like of theprinting apparatus convert the document data into the drawing commandrow and the drawing command row is subjected to the bitmap imaging, itis acceptable that different black generating procedural treatments anddifferent under color removal procedural treatments are to be carriedout respectively on the character part, the line drawing part and thephotograph part of the drawing command row, followed by the bitmapimaging.

Moreover, it is acceptable that a controlling unit for controllingdifferent in-printing ink's total amounts is to be set up for carryingout controls respectively of the character part, the line drawing partand the photograph part of the drawing command row.

Moreover, it is acceptable that the operation portion and the likefunction as an input setting unit for inputting the in-printing ink'stotal amounts adapted respectively to the character part, the linedrawing part and the photograph part of the drawing command row.Hereinafter described is the ink used for the present invention.

A first feature of the ink of the present invention is use of an aqueousink and an aqueous ink set which ink has a low surface tension of 40mN/m or less at 25° C. After studying hard on various measures forimproving dryness of the record image, the present inventors have foundthat adjusting the surface tension of the ink to 40 mN/m or less canbring about a speedy penetration-drying to substantially all recordmaterials. The surface tension of the ink of 40 mN/m or less can betterwetting state of the ink to a head member, thereby even a high-viscosityink of 8 mPa.sec or more (25° C.) can improve frequency response andremarkably improve ejection stability. The ink having the above lowsurface tension can be obtained by combining a polyol (having 8 to 11carbon atoms) or a glycol ether (having 8 to 11 carbon atoms) with ananionic surfactant or a nonionic surfactant.

A second feature of the present invention is a remarkable improvement inprinting quality by using a high-viscosity ink (ink set) of 5 mPa.sec ormore (25° C.), and more preferably 8 mPa-sec or more (25° C.). Alow-viscosity ink of about 3 mPa-sec (25° C.) used for a conventionalinkjet printer has its water content of about 70% by weight, while theink having high viscosity of 8 mPa.sec (25° C.) can render its watercontent of about 50% by weight or less, increasing moisture-evaporationrate (caused when an ink droplet reaches a paper face) 2.0 times to 3.0times. With this, a high-density pigment can increase its cohesion rateon the paper face, thus substantially eliminating the feathering.

A third feature of the present invention is that coloring material inthe ink has a preferable density of 8% by weight or more (solidcontent), and more preferably 10% by weight or more (solid content).Increasing polymer emulsion density or pigment density can increaseink's viscosity, thereby easing cohesion of the pigment on the surfaceof the ink accepting layer of the recording medium and improvingcoloring density and color tone, in addition, substantially eliminatingthe feathering.

A fourth feature of the present invention is that a high-viscositywetting agent is used which is a mixture of glycerin with at least onehigh-viscosity wetting agent selected from the group consisting ofglycerin, 1,3-butanediol, triethylene glycol, 1,6-hexanediol, propyleneglycol, 1,5-pentanediol, diethylene glycol, dipropylene glycol,trimethylol propane, and trimethylol ethane, instead of a low-viscositywetting agent which is a conventional mixture of a ethylene glycol(diethylene glycol) with a glycerin. Using the high-viscosity wettingagent can, in addition to a high pigment density, bring about ahigh-viscosity ink.

The ink composition of the present invention is preferably a recordingink having its ink viscosity of 5 mPa.sec or more, and more preferably 8mPa.sec or more (25° C.), with a structure of the recording ink shownbelow. With a coloring material for printing and water for dispersingthe coloring material as essential compositions, the ink of the presentinvention contains agents added upon necessity such as a wetting agent,a water-soluble organic solvent, one of an anionic surfactant andnonionic surfactant, an emulsion, a preservative, a pH regulator, andthe like. Mixing a wetting agent 1 with a wetting agent 2 is foractivating features of each of the wetting agents and for adjustingviscosity, but the above mixing of the wetting agent 1 and the wettingagent 2 is not always the case.

-   -   (1) Coloring agent    -   (2) Wetting agent 1 (glycerin)    -   (3) Wetting agent 2 (at least one selected from the group        consisting of 1,3-butanediol, triethylene glycol,        1,6-hexanediol, propylene glycol, 1,5-pentanediol, diethylene        glycol, dipropylene glycol, trimethylol propane, and trimethylol        ethane)    -   (4) Water-soluble organic solvent    -   (5) Anionic surfactant or nonionic surfactant    -   (6) At least one of polyol having 8 to 11 carbon atoms and        glycol ether having 8 to 11 carbon atoms    -   (7) Preservative    -   (8) pH regulator    -   (9) Pure water

Hereinafter described are structural elements of each ink.

Examples of a coloring material for the black ink include carbon black.

Preferably used carbon black is the one manufactured by furnace method,channel method and the like, and has a primary particle diameter 15 nmto 40 nm, a specific surface area 50 m²/g to 300 m²/g by BET absorbingmethod, and pH 2 to pH 9. Especially preferable is an acid carbon blackhaving pH 6 or less, which has high density. Alternatively preferableare those so-called a self-dispersion carbon black such as a carbonblack subjected to hypochlorous acid treatment, a carbon black subjectedto sulfonation treatment, a carbon black which is subjected to treatmentwith diazonium compound and introduces anionic dissociation group suchas carboxylic acid.

The black ink using the self-dispersion carbon black is excellent inejection stability, and excellent in image density and character qualitywhen printing is carried out onto the plain paper. Contrary to theabove, short of friction resistance may be caused when the recording iscarried out on to a recording medium (such as gloss paper) that isprovided with an ink absorbing layer on the base material. Forcompensating the friction resistance, the self-dispersion carbon blackmay be added by resin emulsion.

A resin emulsion means an emulsion that has its continuous phase aswater, and has its dispersion phase including the following resincompositions. The examples of the resin compositions of the dispersionphase include acrylic resin, vinyl acetate resin, styrene-butadieneresin, vinyl chloride resin, acryl-styrene resin, butadiene resin,styrene resin, and the like.

According to the preferable aspect of the present invention, the resinis preferred to be a polymer which is a combination of a hydrophilicpart and a hydrophobic part. Particle diameter of the resin composition,as long as the emulsion can be formed, is not particularly limited, butis preferably about 150 nm or less, and more preferably 5 nm to 100 nm.

The resin emulsion can be obtained by mixing the resin particle inwater, or by mixing the resin particle and the surfactant in water. Forexample, an emulsion of acrylic resin is obtained by mixing the acrylicresin and the surfactant in water, and an emulsion of styrene-acrylresin is obtained by mixing the styrene-acryl resin and the surfactantin water.

A preferable ratio (weight ratio) of mixture of resin composition tosurfactant is ordinarily 10:1 to 5:1. Use of the surfactant less thanthe above range is unlikely to form the emulsion, while more than theabove range is likely to decrease waterproof of the ink or deterioratepermeability, which are not preferable.

Ratio of resin (as dispersion phase components of the emulsion) to wateris 100 weight parts of resin relative to 60 weight parts to 400 weightparts of water, and preferably 100 weight parts to 200 weight parts ofwater.

The examples of commercially available resin emulsions include Micro GelE-1002 and Micro Gel E-5002 (styrene-acryl resin emulsion made by NipponPaint), VONCOAT 4001 (acryl resin emulsion made by Dainippon Ink andChemicals Incorporated), VONCOAT 5454 (styrene-acryl resin emulsion madeby Dainippon Ink and Chemicals Incorporated), SAE-1014 (styrene-acrylresin emulsion made by ZEON CORPORATION), Sybynol SK-200 (acryl resinemulsion made by Saiden Chemical Industry Co., Ltd.), and the like.

The ink of the present invention is preferred to contain the resinemulsion having its resin composition of 0.1% by weight to 40% by weightrelative to the ink composition, and more preferably 1% by weight to 25%by weight.

The resin emulsion has properties such as viscosity increase andcohesion, suppresses penetration of coloring composition, and promotesfixation to the record material. Moreover, some types of the resinemulsions may form a coat film on the record material, thereby improvingfriction resistance of the print.

A coloring material for color ink is made of a polymer emulsion whichcomprises a polymer fine particle containing the coloring materialinsoluble in water or unlikely to dissolve in water. Of the presentinvention, the term, “containing coloring material” means at least oneof a first state of sealing the coloring material in the polymer fineparticle and a second state of absorbing the coloring material to asurface of the polymer fine article. In this case, all the coloringmaterials blended with the ink of the present invention are notnecessarily be sealed or absorbed to the polymer fine particle. Instead,within a scope that the effect of the present invention is not lost, thecoloring material can be dispersed in the emulsion. As long as beinginsoluble in water or unlikely to dissolve in water, and having theproperty to be absorbed by the polymer, the above coloring material isnot specifically limited.

Of the present invention, the term “insoluble in water” or the term“unlikely to dissolve in water” means that the coloring material is notdissolved by 10 weight parts or more relative to water 100 weight partsat 20° C. The above “dissolve” means that a visual inspection cannotfind any separation or deposition of the coloring material on thesolution's surface layer or lower layer. The examples of the abovecoloring material include dye (which is oil-soluble, dispersible, andthe like), pigment, and the like. From the view point of good absorptionand sealability, the oil-soluble dye or the dispersible dye ispreferable, while in view of light resistance of the obtained image, thepigment is preferable.

From the view point of efficient impregnation in the polymer fineparticle, each of the dyes of the present invention is preferablydissolved by 2 g/liter or more in an organic solvent such as ketonesolvent, and more preferably 20 g/liter to 600 g/liter.

Examples of the usable color ink pigment for yellow ink include C. I.pigment yellow 1 (fast yellow G), 3, 12 (disazo yellow AAA), 13, 14, 17,23, 24, 34, 35, 37, 42 (yellow iron oxide), 53, 55, 74, 81, 83 (disazoyellow HR), 95, 97, 98, 100, 101, 104, 108, 109, 110, 117, 120, 128,138, 150, 153 and the like.

Examples of the usable color ink pigment for magenta include C. I.pigment red 1, 2, 3, 5, 7, 22 (brilliant fast scarlet), 23, 31, 38, 48:2 (permanent red 2B (Ba)), 48:2 (permanent red 2B (Ca)), 48:3 (permanentred 2B (Sr)), 48:4 (permanent red 2B (Mn)), 49:1, 52:2, 53:1, 57:1(brilliant carmine 6B), 60:1, 63:1, 63:2, 64:1, 81 (rhodamine 6G lake),83, 88, 92, 101 (red iron oxide), 104, 105, 106, 108 (cadmium red), 112,114, 122 (dimethyl quinacridone), 123, 146, 149, 166, 168, 170, 172,177, 178, 179, 185, 190, 193, 209, 219 and the like.

Examples of the usable color ink pigment for cyan include C. I. pigmentblue 1, 2, 15 (copper phthalocyanine blue R), 15:1, 15:2, 15:3(phthalocyanine blue G), 15:4, 15:6 (phthalocyanine blue E), 16, 17:1,56, 60, 63 and the like.

Examples of the usable color ink pigment as intermediate color (for red,green and blue) include the following pigments which may be used aloneor in combination. Moreover, the following pigments can be used fortoning the magenta color and the cyan color.

C. I. pigment red 177, 194, 224, C. I. pigment orange 43, C. I. pigmentviolet 3, 19, 23, 37, and C. I. pigment green 7, 36.

The examples of other proper coloring pigments are described in “TheColour Index Edition 3 (The Society of Dyers and Colourists, 1982).”

For the pigment used as coloring agent, the above dyes can be used incombination for assisting and toning the color.

Blending of the above coloring material is about 10% by weight to 200%by weight relative to the polymer blending, and preferably about 25% byweight to 150% by weight.

The polymer constituting the polymer emulsion can use, for example,vinyl polymer, polyester polymer, polyurethane polymer, and the like.Especially preferred is the vinyl polymer and the polyester polymer,which are those disclosed in JP-A No. 2000-53897, JP-A No. 2000-53898and JP-A No. 2001-139849.

According to a preferred aspect of the present invention, an averagediameter of the polymer fine particles containing the above coloringmaterials is most preferably 0.16 μm or less in the ink.

Content of the polymer fine particle in the ink is preferably 8% byweight to 20% by weight (solid content), and more preferably 8% byweight to 12% by weight.

In terms of the wetting agent and the water-soluble organic solvent, theink of the present invention uses the water as liquid medium. For thepurpose of making a desired material property of the ink, preventingdryness of the ink, and improving dispersion stability, the followingwater-soluble organic solvents are to be used, a plurality of which canbe combined.

Specific examples of the wetting agent and the water-soluble organicsolvent include the following:

-   -   polyhydric alcohols such as ethylene glycol, diethylene glycol,        triethylene glycol, propylene glycol, dipropylene glycol,        tripropylene glycol, tetraethylene glycol, hexylene glycol,        polyethylene glycol, polypropylene glycol, 1,5-pentane diol,        1,6-hexane diol, glycerol, 1,2,6-hexane triol, 1,2,4-butane        triol, 1,2,3-butane triol, petriol, and the like;    -   polyhydric alcohol alkyl ethers such as ethylene glycol        monoethyl ether, ethylene glycol monobutyl ether, diethylene        glycol monomethyl ether, diethylene glycol monoethyl ether,        diethylene glycol monobutyl ether, tetraethylene glycol        monomethyl ether, propylene glycol monoethyl ether, and the        like;    -   polyhydric alcohol aryl ethers such as ethylene glycol        monophenyl ether, ethylene glycol monobenzyl ether, and the        like;    -   nitrogen-contained heterocyclic ring compounds such as        2-pyrrolidone, N-methyl-2-pyrrolidone,        N-hydroxyethyl-2-pyrrolidone, 1,3-dimethyl imidazolidinone,        F-caprolactam, y-butyrolactone, and the like;    -   amides such as formamide, N-methyl formamide, N,N-dimethyl        formamide, and the like;    -   amines such as monoethanol amine, diethanol amine, triethanol        amine, monoethyl amine, diethyl amine, triethyl amine and the        like;    -   sulfur-contained compounds such as dimethyl sulfoxide,        sulfolane, thiodiethanol, and the like; propylene carbonate;        ethylene carbonate; and the like.

Among the above organic solvents, especially preferable are diethyleneglycol, thiodiethanol, polyethylene glycol 200 to 600, triethyleneglycol, glycerol, 1,2,6-hexane triol, 1,2,4-butane triol, petriol,1,5-pentane diol, 2-pyrrolidone, and N-methyl-2-pyrrolidone. The aboveorganic solvents may bring about an excellent effect for preventinginjection failure which may be caused by solubility andmoisture-evaporation.

Other wetting agents preferably contain saccharide. The examples of thesaccharide include monosaccharide, disaccharide, oligosaccharide(including trisaccharide and tetrasaccharide) and other polysaccharide.The examples of the preferable saccharide include glucose, mannose,fructose, ribose, xylose, arabinose, galactose, maltose, cellobiose,lactose, sucrose, trehalose, maltotriose, and the like. Herein, the termpolysaccharide means the saccharide in a broad sense, includingsubstances present extensively in nature such as α-cyclodextrin,cellulose, and the like.

Derivatives of the above saccharides include reduced sugar of the abovesaccharides (for example, sugar alcohol (expressed by a general formulaHOCH₂(CHOH)_(n)CH₂OH (where n is an integer of 2 to 5)), oxidized sugar(for example, aldonic acid, uronic acid, and the like), amino acid,thioic acid, and the like. Especially preferable is the sugar alcohol,the specific examples thereof including maltitol, sorbitol, and thelike.

Content of the above saccharides is from 0.1% by weight to 40% by weightof ink composition, and preferably 0.5% by weight to 30% by weight.

Ratio of the pigment to the wetting agent has a great effect on theejection stability of the ink from the head. High pigment solid contentwith a small blending of the wetting agent may accelerate moistureevaporation in the vicinity of ink meniscus of the nozzle, thus causingejection failure.

Blending of the wetting agent is preferably from 10% by weight to 50% byweight. On the other hand, content of the polymer fine particlecontaining the coloring material is preferably 8% by weight or more, andmore preferably 8% by weight to 20% by weight. With this, the ratio ofthe wetting agent to the polymer fine particle (solid content) is 0.5 to6.25, more preferably 2.0 to 6.0, and most preferably 3.0 to 5.0. Theink within the above range may bring about favorable results in drynesstest, storage stability test, and reliability test.

The surfactant used is anionic or nonionic. Based on combinations of i)types of coloring materials, ii) the wetting agents, and iii) thewater-soluble organic solvent, the surfactant is to be selected suchthat the dispersion stability is not lost.

The examples of the anionic surfactant include salts such aspolyoxyethylene alkylether acetate, dodecylbenzene sulfonate, salt oflauryl acid, polyoxyethylene alkylether sulfate, and the like.

The examples of the nonionic surfactant include polyoxyethylenealkylether, polyoxyethylene alkylester, polyoxyethylene sorbitan fattyacid ester, polyoxyethylene alkyl phenyl ether, polyoxyethylenealkylamine, polyoxyethylene alkylamide, and the like.

The examples of the acetylene glycol surfactant include acetyleneglycols such as 2,4,7,9-tetramethyl-5-decin-4, 7-diol,3,6-dimethyl-4-octyne-3,6-diol, 3,5-dimethyl-1-hexine-3-ol. The examplesof the acetylene glycols include Surfynol 104, Surfynol 82, Surfynol465, Surfynol 485, and Surfynol TG (made by AIR PRODUCTS, U.S.A.),especially Surfynol 465, Surfynol 104 and Surfynol TG show a goodprinting quality.

The surfactants can be used alone or in combination of two or more.

Of the present invention, use of the surfactant can improve wettingproperty to the record paper. The examples of preferable surfactantsinclude polyoxy ethylene alkyl ether acetate, dialkyl sulfosuccinate,polyoxy ethylene alkyl ether, polyoxy ethylene alkyl phenyl ether,polyoxy ethylene polyoxy propylene block copolymer, acetylene glycol,and the like. More specifically, as the anionic surfactant, use of atleast one of polyoxyethylene alkylether acetate (see the followinggeneral formula (I)) and dialkyl sulfosuccinate having branched alkylchain having 5 to 16 carbon chains (see the following general formula(II)) can improve plain paper property and obtain solubility anddispersion stability of the coloring agent.R₁—O—(CH₂CH₂O)_(m)CH₂COOM   (I)(R₁ denotes a branchable alkyl group having 6 to 14 carbon atoms, mdenotes an integer of 3 to 12, M denotes an alkali metal ion, aquaternary ammonium, a quaternary phosphonium, and an alkanolamine.)

(R₂ denotes a branched alkyl group having 5 to 16 carbon atoms, Mdenotes an alkali metal ion, a quaternary ammonium, a quaternaryphosphonium, and an alkanolamine.)

The followimg chemical formulae specifically show the surfactants of thegeneral formula (I) and the surfactants of the general formula (II) withfree acid types.CH₃(CH₂)₁₂O(CH₂CH₂O)₃CH₂COOH   (I-1)CH₃(CH₂)₁₂O(CH₂CH₂O)₄CH₂COOH   (I-2)CH₃(CH₂)₁₂O(CH₂CH₂O)₅CH₂COOH   (I-3)CH₃(CH₂)₁₂O(CH₂CH₂O)₆CH₂COOH   (I-4)

Using lithium ion, quaternary ammonium, and quaternary phosphonium (thelatter two of which expressed by the following formula), as a counterion of the surfactant of the present invention, can present an excellentsolution stability of the surfactant.

(In the above formula, Z denotes nitrogen or phosphor, R₃ to R₆ eachdenote one of hydrogen, alkyl group having 1 to 4 carbon atoms, hydroxyalkyl group having 1 to 4 carbon atoms, and halogenated alkyl grouphaving 1 to 4 carbon atoms.)

The examples of preferable nonion surfactants include polyoxy ethylenealkyl phenyl ether expressed by the following general formula (III),polyoxy ethylene alkyl ether expressed by the following general formula(IV), polyoxy ethylene polyoxy propylene alkyl ethers expressed by thefollowing general formula (V) and general formula (V,), acetylene glycolexpressed by the following general formula (VI). Using the above anionicsurfactants in combination can bring about a synergy effect such aspermeability, thus decreasing color bleeding and character feathering ofthe ink.

(R denotes a branchable hydrocarbon group having 6 to 14 carbon atoms,k=5 to 20)R—(OCH₂CH )₂noH   (IV)(R denotes a branchable hydrocarbon group having 6 to 14 carbon atoms,k=5 to 20)

(R′ denotes a hydrocarbon group having 6 to 14 carbon atoms, m≦20, n≦20)

 (p, q=0˜40)

Setting the ink's pH at 6 or more can bring about the ink's storagestability. In so many occasions, the copy paper and the like used in theoffice have pH of 5 to 6. Recording on so-called a plain paper sheet inthe following recording method can provide a record image having highquality and high resolution: ejecting the ink to the record paper from afine ejection port of 9 μm to 60 μm thus causing a droplet of 3 ng byweight to 5 ng by weight at an injection rate of 5 m/s to 20 m/s, theamount of monochromatic adhesion being set at 1.5 g/m² to 30 g/m²,Steckigt sizing degree of 3 seconds or more in the test method of JISP-8122. When the surfactant expressed by the general formula (II) isused, pH of 9 or more is likely to cause, in the storage, materialchange attributable to decomposition. For use of the surfactantexpressed by the general formula (II), it is preferable to set pH at 6to 9.

The amount of the additives expressed by the general formulas (I), (II),(III), (IV), (V), (V′), and (VI) is in a range from 0.05% by weight to10% by weight, giving a desired permeability to the ink's propertyrequired by the printer system. Less than 0.05% by weight in each casehereinabove may cause the color bleeding to a boundary between twooverlapped colors, while more than 10% by weight in each casehereinabove is likely to cause deposition of the compound itself at lowtemperature thus decreasing reliability.

The surface tension of the present invention is an index of permeabilityinto the paper, especially denoting a dynamic surface tension in a shorttime of 1 second or less after formation of the surface, which isdifferent from a static surface tension measured at a saturation time.JP-A No. 63-31237 discloses a conventional method for measuring adynamic surface tension of 1 second or less, which method is applicable.Of the present invention, however, Wilhelmy surface tension tester whichis of a suspension type was used for measurement. The surface tension ispreferably 40 mJ/m² or less, and more preferably 35 mJ/m² or less forobtaining excellent fixing property and dryness.

Of the present invention, the polyol or the glycol ether has 8 to 11carbon atoms. Adding a partly water-soluble polyol and/or glycol(namely, solubility of 0.1% by weight to less than 4.5% by weight inwater of 25° C.) by 0.1% by weight to 10.0% by weight relative to atotal weight of the recording ink can improve the ink's wetting propertyto a thermal element, thus bringing about ejection stability andfrequency stability even with a small amount of additives.

Preferable examples of the above include the following.

-   -   (1) 2-ethyl-1,3-hexanediol Solubility: 4.2% (at 20° C.)    -   (2) 2,2,4-trimethyl-1,3-pentanediol Solubility: 2.0% (at 25° C.)

In the water of 25° C., a penetrant (polyol, glycol ether) havingsolubility of 0.1% by weight to less than 4.5% by weight can bring aboutan advantage in that the penetration property is very high, in place ofthe low solubility. Thus, in the water of 25° C., it is possible to makean ink with a very high penetration property by combining the penetrant(having solubility of 0.1% by weight to less than 4.5% by weight) withother solvent or with other surfactant.

The ink of the present invention may be added by a conventional additiveother than the coloring agent, the solvent, the surfactant and the likewhich are described above.

The examples of usable preservatives (corrosion and mold) include sodiumdehydroacetate, sodium sorbate, 2-pyridinethiol-1-oxide sodium, sodiumbenzoate, pentachlorophenol sodium, and the like.

The examples of pH regulators include arbitrary substances capable ofregulating pH to 7 or more without causing a harmful effect on the inkthus regulated.

The other examples of pH regulator include amines such as diethanolamine, triethanol amine, and the like; hydrides of alkali metal elementssuch as lithium hydroxide, sodium hydroxide, potassium hydroxide, andthe like; ammonium hydroxide; quaternary ammonium hydroxide; quaternaryphosphonium hydroxide; carbonates of alkali metal such as lithiumcarbonate, sodium carbonate, potassium carbonate, and the like; and thelike.

The examples of chelate reagent include ethylene diamine tetraaceticacid sodium, nitrilotriacetic acid sodium, hydroxyethyl ethylene diaminetriacetic acid sodium, diethylene triamine acetic acid pentasodium,uramil diacetic acid sodium, and the like.

The examples of rustproof agent include sulphurous acid, sodiumthiosulfate, ammonium thiodiglycolate, diisopropyl ammonium nitrite,pentaerythritol tetranitrate, dicyclohexyl ammonium nitrite, and thelike.

Alternatively, according to the object, a water-soluble ultravioletabsorbent, a water-soluble infrared absorbent, and the like can beadded.

EXAMPLE

Hereinafter described are examples and comparative examples of thepresent invention. The present invention is, however, not limitedthereto.

<Preparation of Ink>

Coloring Agent Preparation Example 1

Preparation of Phthalocyanine Pigment-Contained Polymer Fine ParticleDispersoid

Based on the preparation example 3 of JP-A No. 2001-139849, thefollowing operation was carried out.

(1) Preparation of Polymer Solution

At first, inside of a 1 L of flask equipped with a mechanical stirrer, athermometer, a nitrogen gas introducing tube, a reflux tube, and adroplet funnel was sufficiently substituted with a nitrogen gas.

Then, a mixture of styrene 100.8 g, acrylic acid 25.2 g, laurylmethacrylate 108.0 g, polyethylene glycol methacrylate 36.0 g,hydroxyethyl methacrylate 60.0 g, styrene macromer (AS-6 made byToagosei Co., Ltd.) 36.0 g, mercapto ethanol 3.6 g, azobis dimethylvaleronitrile 2.4 g, and methyl ethyl ketone 18 g was dropped in theflask for 2.5 hours.

After completion of the drop, a mixture of azobis dimethyl valeronitrile0.8 g and methyl ethyl ketone 18 g was dropped in the flask for 0.5hour. After maturing the resultant for 1 hour at 65 ° C., azobisdimethyl valeronitrile 0.8 g was added, followed by a further maturingfor 1 hour.

After completion of the reaction, methyl ethyl ketone 364 g was added,to thereby obtain a polymer solution 800 g having density of 50% byweight.

(2) Preparation of Water Dispersoid of Polymer Fine Particle

The polymer solution 28 g thus obtained in (1) above, phthalocyaninepigment 26 g (TGR-SD made by Dainippon Ink and Chemicals Incorporated),1 mol/L of potassium hydroxide solution 13.6 g, methyl ethyl ketone 20g, and ion exchanged water 30 g were sufficiently stirred. Then, threeroll mills were used for mixing-kneading 20 times. The thus obtainedpaste was inputted in an ion exchange water 200 g, sufficiently stirred,then the methyl ethyl ketone and the water were distilled with anevaporator, to thereby obtain a blue polymer fine particle dispersoid.

Measured with a micro track UPA, the polymer fine particle showed anaverage particle diameter (D 50%) of 93 nm.

Coloring Agent Preparation Example 2

Preparation of Dimethylquinacridone Pigment-Contained Polymer FineParticle Dispersoid

The preparation example 1 was likewise repeated except that thephthalocyanine pigment in the preparation example 1 was replaced with apigment red 122, to thereby obtain a purple polymer fine particledispersoid. Measured with the micro track UPA, the polymer fine particleshowed an average particle diameter (D 50%) of 127 nm.

Coloring Agent Preparation Example 3

Preparation of Monoazo Yellow Pigment-Contained Polymer Fine ParticleDispersoid

The preparation example 1 was likewise repeated except that thephthalocyanine pigment in the preparation example 1 was replaced with apigment yellow 74, to thereby obtain a yellow polymer fine particledispersoid.

Measured with the micro track UPA, the polymer fine particle showed anaverage particle diameter (D 50%) of 76 nm.

Coloring Agent Preparation Example 4

Preparation of Carbon Black Dispersing Solution Subjected to DiazoCompound Treatment

Carbon black 100 g (surface 230 m²/g, DBP oil absorption 70 ml/100 g)and p-amino-N-benzoic acid 34 g were mixed and dispersed in water 750 g,then nitric acid 16 g was dropped therein, and then the mixture wasstirred at 70° C. After 5 minutes, a solution of water 50 g with sodiumnitrite 11 g dissolved therein was added. Another stirring for 1 hour.The thus obtained slurry was diluted to 10 times, and was subjected to acentrifugal treatment for removing coarse grains. pH was regulated to 8to 9 with diethanol amine. An ultrafiltration was carried out fordesalinization-enrichment, to thereby obtain a carbon black dispersingsolution with its pigment density 15% by weight. The resultant waspolypropylene-filtered (0.5 μm), to thereby obtain a carbon blackdispersing solution 1. Measured with the micro track UPA, the carbonblack dispersing solution 1 showed an average particle diameter (D 50%)of 99 nm.

Coloring Agent Preparation Example 5

Preparation of Carbon Black Dispersing Solution Subjected toHypochlorous Acid Treatment

A commercially-available acid carbon black 300 g (Monarch 1300 made byCabot Corporation) having pH 2.5 was sufficiently mixed with water 1000milliliter, then a hypochlorous acid soda (effective chlorine density12%) 450 g was dropped therein, and then stirred for 8 hours at 100° C.to 105° C. Another hypochlorous acid soda (effective chlorine density12%) 100 g was added to the solution, followed by dispersion for 3 hourswith a horizontal dispersing machine. The thus obtained slurry wasdiluted to 10 times with water, pH was regulated with lithium hydroxide,then an ultrafiltration was carried out for desalinization-enrichment toelectric conductivity of 0.2 mS/cm, to thereby obtain a carbon blackdispersing solution having pigment density of 15%. The thus obtainedcarbon black dispersing solution was subjected to a centrifugaltreatment for removing coarse grains, and then subjected to a nylonfilter of 1 micron, to thereby obtain a carbon black dispersing solution2. Measured with the micro track UPA, the carbon black dispersingsolution 2 showed an average particle diameter (D 50%) of 95 nm.

Ink a

An ink composition having the following prescription was prepared, and alithium hydroxide 10% solution was used for regulating pH to 9. Then, amembrane filter having an average pore diameter of 0.8 μm was used forfiltering, to thereby obtain an ink composition.

Coloring Agent, Preparation Example 4

Carbon black dispersion solution 1 8.0% by weight subjected to diazocompound treatment (solid content) 1,4-butanediol 22.5% by weightGlycerine 7.5% by weight N-methyl-2-pyrrolidone 2.0% by weightSurfactant of specific example (II-2) 2.0% by weight2,2,4-trimethyl-1,3-pentane diol 2.0% by weight PROXEL LV (preservative)0.2% by weight Ion exchanged water BalanceInk b

Preparation of the ink a was likewise carried out except that thefollowing compositions were used, to thereby prepare an ink compositionby regulating pH to 9 using lithium hydroxide.

Coloring Agent, Preparation Example 1

Phthalocyanine pigment-contained 15.0% by weight polymer fine particledispersoid (solid content) 1,5-pentanediol 15.0% by weight Glycerine15.0% by weight N-hydroxy ethyl-2-pyrrolidone 2.0% by weight Surfactantof specific example (II-3) 2.0% by weight 2-ethyl-1,3-hexane diol 2.0%by weight PROXEL LV (preservative) 0.2% by weight Ion exchanged waterBalanceInk c

Preparation of the ink a was likewise carried out except that thefollowing compositions were used, to thereby prepare an ink compositionby regulating pH to 9 using lithium hydroxide.

Coloring Agent, Preparation Example 2

Dimethyl quinacridone pigment-contained 15.0% by weight polymer fineparticle dispersoid (solid content) 1,6-hexanediol 22.5% by weightGlycerine 7.5% by weight 2-pyrrolidone 3.0% by weight Surfactant ofspecific example (II-4) 2.0% by weight 2,2,4,-trimethyl-1,3-pentane diol2.0% by weight PROXEL LV (preservative) 0.2% by weight Ion exchangedwater BalanceInk d

Preparation of the ink a was likewise carried out except that thefollowing compositions were used, to thereby prepare an ink compositionby regulating pH to 9 using lithium hydroxide.

Coloring Agent, Preparation Example 3

Monoazo yellow pigment-contained 15.0% by weight polymer fine particledispersoid 2-methyl-2,4-pentanediol 22.5% by weight (solid content)Glycerine 7.5% by weight N-methyl-2-pyrrolidone 5.0% by weight2-pyrrolidone 3.0% by weight Surfactant of general formula (III) 2.0% byweight (R = n-hexyl group, k = 5) 2-ethyl-1,3-hexane diol 2.0% by weight2,2,4,-trimethyl-1,3-pentane diol 2.0% by weight PROXEL LV(preservative) 0.2% by weight Ion exchanged water BalanceInk e

An ink composition having the following prescription was prepared, and alithium hydroxide 10% solution was used for regulating pH to 9. Then, amembrane filter having an average pore diameter of 0.8 μm was used forfiltering, to thereby obtain an ink composition.

Coloring Agent, Preparation Example 1

Phthalocyanine pigment-contained polymer 5.0% by weight fine particledispersoid (solid content) Ethylene glycol 15.0% by weight Glycerine5.0% by weight 2-pyrrolidone 2.0% by weight ECTD-3NEX (anionicsurfactant made by Nikko Chemicals) 1.0% by weight2-ethyl-1,3-hexanediol 2.0% by weight Acrylic resin emulsion 3.0% byweight PROXEL LV (preservative) 0.2% by weight Ion exchanged waterBalanceInk f

Preparation of the ink a was likewise carried out except that thefollowing compositions were used, to thereby prepare an ink compositionby regulating pH to 9 using lithium hydroxide.

Coloring Agent, Preparation Example 2

Dimethyl quinacridone pigment-contained 6.0% by weight polymer fineparticle dispersoid (solid content) Diethylene glycol 15.0% by weightGlycerol 5.0% by weight N-methyl-2-pyrrolidone 2.0% by weight ECTD-6NEX(anionic surfactant made by Nikko Chemicals) 1.0% by weight2,2,4-trimethyl-1,3-pentane diol 2.0% by weight PROXEL LV (preservative)0.2% by weight Ion exchanged water BalanceInk g

Preparation of the ink a was likewise carried out except that thefollowing compositions were used, to thereby prepare an ink compositionby regulating pH to 9 using lithium hydroxide.

Coloring Agent, Preparation Example 3

Monoazo yellow pigment-contained polymer 5.0% by weight fine particledispersoid (solid content) Triethylene glycol 15.0% by weight Glycerin5.0% by weight N-hydroxy ethyl-2-pyrrolidone 2.0% by weight Surfactantexpressed by general formula (IV) (R = C₁₃H₂₇, n = 8) 1.0% by weight2-ethyl-1,3-hexane diol 2.0% by weight Acrylic rein emulsion 3.0% byweight PROXEL LV (preservative) 0.2% by weight Ion exchanged waterBalanceInk h

Preparation of the ink a was likewise carried out except that thefollowing compositions were used, to thereby prepare an ink compositionby regulating pH to 9 using lithium hydroxide.

Coloring Agent, Preparation Example 4

Carbon black dispersoid subjected to diazo 4.0% by weight compoundtreatment (solid content) Ethylene glycol 15.0% by weight Glycerine 2.0%by weight 2-pyrrolidone 2.0% by weight ECTD-6NEX (Anionic surfactantmade by Nikko Chemicals) 1.0% by weight 2,2,4-trimethyl-1,3-pentanediol2.0% by weight PROXEL LV (preservative) 0.2% by weight Ion exchangedwater Balance[214]Ink i

Preparation of the ink a was likewise carried out except that thefollowing compositions were used, to thereby prepare an ink compositionby regulating pH to 9 using lithium hydroxide.

Coloring Agent, Preparation Example 5

Carbon black dispersoid 2 subjected 8.0% by weight to hypochlorous acidtreatment (solid content) Acrylic resin emulsion 3.0% by weight (solidcontent) Triethylene glycol 15.0% by weight Glycerol 10.0% by weight2-hydroxy ethyl pyrrolidone 5.0% by weight Surfactant of specificexample (I-2) 1.0% by weight 2-ethyl-1,3-hexane diol 1.0% by weightSodium dehydroacetate 0.2% by weight Ion exchanged water Balance

Table 3-1 to Table 3-3 show i) coloring agent solid content density(pigment and emulsion), ii) wetting agent density and ink viscosity ofthe compositions of the ink a to the ink i. TABLE 3-1 Coloring agentsolid content Wetting agent Viscosity density density mPa · sec (% byweight) (% by weight) (25° C.) Ink set A Ink b CYAN 15.0 30.0 9.3 Ink cMAG 15.0 30.0 10.3 Ink d YEL 15.0 30.0 9.6 Ink a Bk 8.0 30.0 8.0(self-dis- persion)

TABLE 3-2 Coloring agent solid content Wetting agent Viscosity densitydensity mPa · sec (% by weight) (% by weight) (25° C.) Ink set B Ink eCYAN 5.0 20.0 2.6 Ink f MAG 6.0 20.0 2.9 Ink g YEL 5.0 20.0 2.8 Ink h Bk4.0 20.0 3.2 (self-dis- persion)

TABLE 3-3 Coloring agent solid content Wetting agent Viscosity densitydensity mPa · sec (% by weight) (% by weight) (25° C.) Ink set C Ink bCYAN 15.0 30.0 9.3 Ink c MAG 15.0 30.0 10.3 Ink d YEL 15.0 30.0 9.6 Inki Bk 11.0 30.0 9.3 (self-dis- persion + emulsion)Explanation of Recording MediumRecording Medium 1 (OHP Sheet)

Alumina sol 100 g (18% by weight, solid content) synthesized byhydrolysis-peptisation of aluminum alkoxide was mixed with polyvinylalcohol 6.2% by weight solution 32 g, to thereby prepare a coatingsolution. The coating solution was applied on to a polyethyleneterephthalate film (thickness 100 μm, white) using a bar coater in sucha manner as to obtain application amount after drying of 26 g/m²,followed by drying, to thereby form a pseudo-boehmite layer. Then, asilica sol coating solution made from i) a silica sol having a primaryparticle diameter 10 nm to 20 nm and ii) a polyvinyl alcohol copolymer(branded as R-polymer-R-1130 made by KURARAY CO., LTD.) having silanolgroup was applied in such a manner as to have a silica gel layerthickness after drying of 1 μm, followed by drying, followed by heattreatment at 140° C., to thereby obtain an OHP sheet.

Recording Medium 2 (Gloss Paper)

On both sides of a base paper sheet having basis weight 83 g/m² andsmoothness 200 second, a polyethylene resin coat layer (surface sidethereof contains i. anatase titanium dioxide pigment subjected tosurface treatment, and ii. zinc stearate) was coated(melting-extruding), to thereby prepare a resin coat paper support foran inkjet record sheet. A resin face on a surface side of the resin coatpaper support was subjected to a corona discharge. Then, an inkjetaccepting layer coating solution composed of i) 5% solution 16.6% byweight of polyvinyl alcohol (saponification 98.5 mol %, averagepolymerization 1700), ii) a mixture (2%, 1 % by weight) of methanol (ofsulfosuccinate-2-ethyl hexyl ester salt) and water, iii) colloidalsilica of drying weight 4.5% by weight (with a needle colloidal silicaas a base, a silica (SiO₂ conversion) was cationically modified usingabout 6.2% by weight aluminum hydroxide at Al₂O₃ conversion, to therebyprepare a needle colloidal silica (made by Nissan Chemical Industries,Ltd.)), and iv) pure water of remaining % by weight was applied with acoater in such a manner as to have dry weight 10 g/m², followed bydrying, to thereby obtain an inkjet gloss paper sheet.

Recording Medium 3 (Plain Paper)

“My paper” (plain paper for electrophotography; made by NBS Ricoh)

Recording Medium 4 (Mat Coat Paper)

“Image chroma mat finishing (super fine grade” (Inkjet Paper; made byFuji Photo Film Co., Ltd.)

Then, using the above recording mediums and the ink a to the ink i, thefollowing tests were carried out using the ink set A, the ink set B andthe ink set C composed of cyan, magenta, yellow and black, as is seen inTable 3-1, Table 3-2 and Table 3-3.

A modified ink-jet printer EM-900C (made by Seiko Epson Corporation) wasused for printing on each recording medium by varying the head's drivingvoltage, frequency and pulse width. Printing patters were categorizedinto i) single color solid pattern of C, M and Y, ii) double solidpattern of B, G and R, and iii) solid pattern of K. The solid patternsof K were categorized into i) black ink (one color) when black ink isused, and ii) cyan, magenta and yellow (three colors) when black is notused. Moreover, an ink for the solid printing was likewise used for thecharacter printing. Printing conditions: Mj 35 pl, Vj 20 m/sec,frequency 1 kHz, recording density 720 dpi, and one pass printing. Theink's total amount controlling value (denoted by ink's weight per unitarea): 22 g/m² for OHP sheet, 20 g/m² for gloss paper, 17 g/m² for plainpaper, and 25 g/m² for mat coat paper.

After the printing-drying, the image density (C, M, Y, K) and thefriction resistance (K) were evaluated. On the gloss paper, the glossfeeling of the image was evaluated.

In terms of the image density: Reflection density of the gloss paper,the plain paper, and the mat coat paper was measured with X-Rite938,while a transparent density of the OHP sheet was measured withX-Rite910T.

By making five reciprocations of the K image part with a clock meter towhich a line cloth is attached, the friction resistance was determinedreferring to colored degree of the line cloth, based on the followingcriteria.

Results are shown in Table 4-1, Table 4-2, Table 4-3 and Table 4-4; andTable 5-1, Table 5-2, Table 5-3 and Table 5-4, where C denotes cyan, Mdenotes magenta, Y denotes yellow and K denotes black.

(Criteria)

Friction Resistance

-   -   A: Line cloth is scarcely colored.    -   B: Line cloth is slightly colored.    -   C: Line cloth is obviously colored.    -   D: Line cloth is densely colored.        (Image Gloss Feeling)

The gloss paper was subjected to the visual inspection of the imagegloss.

-   -   A: Excellent    -   B: Good    -   C: Slightly deteriorated

D: Deteriorated TABLE 4-1 Recording Friction Image medium Ink set ModeInk used Image density resistance gloss Recording Ink set A Color modeThree colors C: 1.81, M: 1.34 B — Present invention medium 1 (CMY) Y:1.06, K: 1.28 (OHP sheet) Four colors C: 1.82, M: 1.32 D — Comparativeexample (CMYK) Y: 1.04, K: 1.34 Monochrome Three colors K: 1.27 B —Present invention mode (CMY) One color (K) K: 1.33 D — Comparativeexample

TABLE 4-2 Recording Friction Image medium Ink set Mode Ink used Imagedensity resistance gloss Recording Ink set A Color mode Three colors C:2.15, M: 1.73 B B Present invention medium 2 (CMY) Y: 1.45, K: 1.85(gloss paper) Four colors C: 2.13, M: 1.72 D D Comparative example(CMYK) Y: 1.45, K: 1.90 Monochrome Three colors K: 1.86 B B Presentinvention mode (CMY) One color (K) K: 1.92 D D Comparative example

TABLE 4-3 Recording Friction Image medium Ink set Mode Ink used Imagedensity resistance gloss Recording Ink set A Color mode Four colors C:1.33, M: 1.28 B — Present invention medium 3 (CMYK) Y: 1.22, K: 1.42(plain paper) Monochrome One color (K) K: 1.46 B — Present inventionmode Ink set B Color mode Four colors C: 1.01, M: 0.98 B — Presentinvention (CMYK) Y: 0.89, K: 1.10 Monochrome One color (K) K: 1.08 B —Present invention mode

TABLE 4-4 Recording Friction Image medium Ink set Mode Ink used Imagedensity resistance gloss Recording Ink set A Color mode Four colors C:1.50, M: 1.45 B — Present invention medium 4 (CMYK) Y: 1.11, K: 1.54(mat coat paper) Monochrome One color (K) K: 1.55 B — Present inventionmode

TABLE 5-1 Recording Friction Image medium Ink set Mode Ink used Imagedensity resistance gloss Recording Ink set C Color mode Four colors C:1.81, M: 1.34 B — Present invention medium 1 (CMYK) Y: 1.06, K: 1.34(OHP sheet) Monochrome One color (K) K: 1.34 B — Present invention modeFour colors K: 1.33 B — Present invention (CMYK)

TABLE 5-2 Recording Friction Image medium Ink set Mode Ink used Imagedensity resistance gloss Recording Ink set C Color mode Four colors C:2.15, M: 1.73 B B Present invention medium 2 (CMYK) Y: 1.45, K: 1.90(gloss paper) Monochrome One color (K) K: 1.92 B B Present inventionmode Four colors K: 1.89 B B Present invention (CMYK)

TABLE 5-3 Recording Friction Image medium Ink set Mode Ink used Imagedensity resistance gloss Recording Ink set C Color mode Four colors C:1.33, M: 1.28 B — Present invention medium 3 (CMYK) Y: 1.22, K: 1.42(plain paper) Monochrome One color (K) K: 1.46 B — Present inventionmode Four colors K: 1.44 B — Present invention (CMYK)

TABLE 5-4 Recording Friction Image medium Ink set Mode Ink used Imagedensity resistance gloss Recording Ink set C Color mode Four colors C:1.50, M: 1.45 B — Present invention medium 4 (CMYK) Y: 1.11, K: 1.55(mat coat paper) Monochrome One color (K) K: 1.57 B — Present inventionmode Four colors K: 1.54 B — Present invention (CMYK)

The ink's total control value more than the above values caused bleedingto two-color boundary, and caused boldness to two-color character andthree-color character.

The present invention selecting the type of inks according to the typeof recording medium and the printing mode can record a high-grade image.

Effecting the feature of an ink containing i) a black ink containing aself-dispersion carbon black which is higher in density and lower insurface tension than the conventional ink and ii) a color ink containingcolored polymer fine particle, the present invention can record ahigh-grade image having high printing density, capable of forming asharp image and excellent in rigidity (waterproof, light proof, frictionresistance and the like).

Moreover, controlling the ink's total amount of the color-overlappedpart can record the image with improved image quality in terms ofgradation.

1. An inkjet recording apparatus, comprising: a black ink ejectingportion configured to eject a black ink containing a self-dispersionpigment; color ink ejecting portions configured to eject, respectively,a cyan ink, a magenta ink and a yellow ink which comprise a polymeremulsion which comprises a polymer fine particle containing a coloringmaterial which is insoluble in water or slightly soluble in water; and arecording-controlling unit configured to control recording, wherein theblack ink ejecting portion and the color ink ejecting portion scanrelative to a recording medium, to thereby record an image on therecording medium, and wherein, when the recording medium is opticallytransparent and is provided, on a transparent base material thereof,with an ink accepting layer, the recording-controlling unit controlsrecording on the recording medium such that the color ink ejectingportion is used for recording a monochrome image and a color image whichhas a plurality of colors, leaving the black ink ejecting portionsubstantially free from being used.
 2. The inkjet recording apparatusaccording to claim 1, wherein the optically transparent recording mediumprovided with the ink accepting layer is an OHP sheet.
 3. The inkjetrecording apparatus according to claim 1, wherein a density of the inkis 5 mPa.sec or more at 25° C.
 4. The inkjet recording apparatusaccording to claim 1, wherein the color ink comprises: the polymeremulsion which comprises the polymer fine particle containing thecoloring material which is insoluble in water or slightly soluble inwater; at least one wetting agent selected from the group consisting ofglycerin, 1,3-butanediol, triethylene glycol, 1,6-hexanediol, propyleneglycol, 1,5-pentanediol, diethylene glycol, dipropylene glycol,trimethylol propane, and trimethylol ethane; at least one of a polyolhaving 8 to 11 carbon atoms, and a glycol ether having 8 to 11 carbonatoms; one of an anionic surfactant and a nonionic surfactant; awater-soluble organic solvent; and water.
 5. The inkjet recordingapparatus according to claim 1, wherein the black ink comprises: theself-dispersion pigment; at least one wetting agent selected from thegroup consisting of glycerin, 1,3-butanecdiol, triethylene glycol,1,6-hexanediol, propylene glycol, 1,5-pentanediol, diethylene glycol,dipropylene glycol, trimethylol propane, and trimethylol ethane; atleast one of a polyol having 8 to 11 carbon atoms, and a glycol etherhaving 8 to 11 carbon atoms; one of an anionic surfactant and a nonionicsurfactant; a water-soluble organic solvent; and water.
 6. An inkjetrecording method, comprising: using an inkjet recording apparatus whichcomprises: a black ink ejecting portion configured to eject a black inkcontaining a self-dispersion pigment; color ink ejecting portionsconfigured to eject, respectively, a cyan ink, a magenta ink and ayellow ink which comprise a polymer emulsion which comprises a polymerfine particle containing a coloring material which is insoluble in wateror slightly soluble in water; and a recording-controlling unitconfigured to control recording, wherein the black ink ejecting portionand the color ink ejecting portion scan relative to a recording medium,to thereby record an image on the recording medium, and wherein, whenthe recording medium is optically transparent and is provided, on atransparent base material thereof, with an ink accepting layer, therecording-controlling unit controls recording on the recording mediumsuch that the color ink ejecting portion is used for recording amonochrome image and a color image which has a plurality of colors,leaving the black ink ejecting portion substantially free from beingused, wherein, when the recording medium is optically transparent and isprovided, on the transparent base material thereof, with the inkaccepting layer, the inkjet recording method uses the color ink forrecording the monochrome image and the color image which has a pluralityof colors, leaving the black ink substantially free from being used. 7.The inkjet recording method according to claim 6, wherein the opticallytransparent recording medium provided with the ink accepting layer is anOHP sheet.
 8. The inkjet recording method according to claim 6, whereina density of the ink is 5 mPa.sec or more at 25° C.
 9. The inkjetrecording method according to claim 6, wherein the color ink comprises:the polymer emulsion which comprises the polymer fine particlecontaining the coloring material which is insoluble in water or slightlysoluble in water; at least one wetting agent selected from the groupconsisting of glycerin, 1,3-butanediol, triethylene glycol,1,6-hexanediol, propylene glycol, 1,5-pentanediol, diethylene glycol,dipropylene glycol, trimethylol propane, and trimethylol ethane; atleast one of a polyol having 8 to 11 carbon atoms, and a glycol etherhaving 8 to 11 carbon atoms; one of an anionic surfactant and a nonionicsurfactant; a water-soluble organic solvent; and water.
 10. The inkjetrecording method according to claim 6, wherein the black ink comprises:the self-dispersion pigment; at least one wetting agent selected fromthe group consisting of glycerin, 1,3-butanediol, triethylene glycol,1,6-hexanediol, propylene glycol, 1,5-pentanediol, diethylene glycol,dipropyfene glycol, trimethylol propane, and trimethylol ethane; atleast one of a polyol having 8 to 11 carbon atoms, and a glycol etherhaving 8 to 11 carbon atoms; one of an anionic surfactant and a nonionicsurfactant; a water-soluble organic solvent; and water.
 11. An inkjetrecording apparatus, comprising: a black ink ejecting portion configuredto eject a black ink containing a self-dispersion pigment; color inkejecting portions configured to eject, respectively, a cyan ink, amagenta ink and a yellow ink which comprise a polymer emulsion whichcomprises a polymer fine particle containing a coloring material whichis insoluble in water or slightly soluble in water; and arecording-controlling unit configured to control recording, wherein theblack ink ejecting portion and the color ink ejecting portion scanrelative to a recording medium, to thereby record an image on therecording medium, wherein, when the recording medium is provided, on anopaque base material thereof, with an ink accepting layer which has asurface having a gloss, the recording-controlling unit controlsrecording on the recording medium such that the color ink ejectingportion is used for recording a monochrome image and a color image whichhas a plurality of colors, leaving the black ink ejecting portionsubstantially free from being used.
 12. The inkjet recording apparatusaccording to claim 11, wherein a density of the ink is 5 mPa.sec or moreat 25° C.
 13. The inkjet recording apparatus according to claim 11,wherein the color ink comprises: the polymer emulsion which comprisesthe polymer fine particle containing the coloring material which isinsoluble in water or slightly soluble in water; at least one wettingagent selected from the group consisting of glycerin, 1,3-butanecdiol,triethylene glycol, 1,6-hexanediol, propylene glycol, 1,5-pentanediol,diethylene glycol, dipropylene glycol, trimethylol propane, andtrimethylol ethane; at least one of a polyol having 8 to 11 carbonatoms, and a glycol ether having 8 to 11 carbon atoms; one of an anionicsurfactant and a nonionic surfactant; a water-soluble organic solvent;and water.
 14. The inkjet recording apparatus according to claim 11,wherein the black ink comprises: the self-dispersion pigment; at leastone wetting agent selected from the group consisting of glycerin,1,3-butanediol, triethylene glycol, 1,6-hexanediol, propylene glycol,1,5-pentanediol, diethylene glycol, dipropylene glycol, trimethylolpropane, and trimethylol ethane; at least one of a polyol having 8 to 11carbon atoms, and a glycol ether having 8 to 11 carbon atoms; one of ananionic surfactant and a nonionic surfactant; a water-soluble organicsolvent; and water.
 15. An inkjet recording method using an inkjetrecording apparatus which comprises: a black ink ejecting portionconfigured to eject a black ink containing a self-dispersion pigment;color ink ejecting portions configured to eject, respectively, a cyanink, a magenta ink and a yellow ink which comprise a polymer emulsionwhich comprises a polymer fine particle containing a coloring materialwhich is insoluble in water or slightly soluble in water; and arecording-controlling unit configured to control recording, wherein theblack ink ejecting portion and the color ink ejecting portion scanrelative to a recording medium, to thereby record an image on therecording medium, wherein, when the recording medium is provided, on anopaque base material thereof, with an ink accepting layer which has asurface having a gloss, the recording-controlling unit controlsrecording on the recording medium such that the color ink ejectingportion is used for recording a monochrome image and a color image whichhas a plurality of colors, leaving the black ink ejecting portionsubstantially free from being used, wherein, when the recording mediumis provided, on the opaque base material thereof, with the ink acceptinglayer which has the surface having the gloss, the inkjet recordingmethod uses the color ink for recording the monochrome image and thecolor image which has a plurality of colors, leaving the black inksubstantially free from being used.
 16. The inkjet recording methodaccording to claim 15, wherein a density of the ink is 5 mPa.sec or moreat 25° C.
 17. The inkjet recording method according to claim 15, whereinthe color ink comprises: the polymer emulsion which comprises thepolymer fine particle containing the coloring material which isinsoluble in water or slightly soluble in water; at least one wettingagent selected from the group consisting of glycerin, 1,3-butanediol,triethylene glycol, 1,6-hexanediol, propylene glycol, 1,5-pentanediol,diethylene glycol, dipropylene glycol, trimethylol propane, andtrimethylol ethane; at least one of a polyol having 8 to 11 carbonatoms, and a glycol ether having 8 to 11 carbon atoms; one of an anionicsurfactant and a nonionic surfactant; a water-soluble organic solvent;and water.
 18. The inkjet recording method according to claim 15,wherein the black ink comprises: the self-dispersion pigment; at leastone wetting agent selected from the group consisting of glycerin,1,3-butanediol, triethylene glycol, 1,6-hexanediol, propylene glycol,1,5-pentanediol, diethylene glycol, dipropylene glycol, trimethylolpropane, and trimethylol ethane; at least one of a polyol having 8 to 11carbon atoms, and a glycol ether having 8 to 11 carbon atoms; one of ananionic surfactant and a nonionic surfactant; a water-soluble organicsolvent; and water.
 19. An inkjet recording apparatus, comprising: ablack ink ejecting portion configured to eject a black ink containing aself-dispersion pigment; and color ink ejecting portions configured toeject, respectively, a cyan ink, a magenta ink and a yellow ink whichcomprise a polymer emulsion which comprises a polymer fine particlecontaining a coloring material which is insoluble in water or slightlysoluble in water; and a recording-controlling unit configured to controlrecording, wherein the black ink ejecting portion and the color inkejecting portion scan relative to a recording medium, to thereby recordan image on the recording medium, wherein, when a color image isrecorded on a plain paper sheet and a black color area in the colorimage is recorded, the recording-controlling unit controls recording onthe recording medium such that the black ink ejecting portion and thecolor ink ejecting portion are used in combination.
 20. The inkjetrecording apparatus according to claim 19, wherein when recording amonochrome image on the plain paper sheet, the recording-controllingunit carries out the controlling such that the black ink ejectingportion is used for the recording, leaving the color ink ejectingportion substantially free from being used.
 21. The inkjet recordingapparatus according to claim 19, wherein when recording a monochromeimage on the plain paper sheet, the recording-controlling unit carriesout the controlling such that the black ink ejecting portion and thecolor ink ejecting portion are used in combination for the recording.22. The inkjet recording apparatus according to claim 19, wherein adensity of the ink is 5 mPa.sec or more at 25° C.
 23. The inkjetrecording apparatus according to claim 19, wherein the color inkcomprises: the polymer emulsion which comprises the polymer fineparticle containing the coloring material which is insoluble in water orslightly soluble in water; at least one wetting agent selected from thegroup consisting of glycerin, 1,3-butanediol, triethylene glycol,1,6-hexanediol, propylene glycol, 1,5-pentanediol, diethylene glycol,dipropylene glycol, trimethylol propane, and trimethylol ethane; atleast one of a polyol having 8 to 11 carbon atoms, and a glycol etherhaving 8 to 11 carbon atoms; one of an anionic surfactant and a nonionicsurfactant; a water-soluble organic solvent; and water.
 24. The inkjetrecording apparatus according to claim 7, wherein the black inkcomprises: the self-dispersion pigment; at least one wetting agentselected from the group consisting of glycerin, 1,3-butanediol,triethylene glycol, 1,6-hexanediol, propylene glycol, 1,5-pentanediol,diethylene glycol, dipropylene glycol, trimethylol propane, andtrimethylol ethane; at least one of a polyol having 8 to 11 carbonatoms, and a glycol ether having 8 to 11 carbon atoms; one of an anionicsurfactant and a nonionic surfactant; a water-soluble organic solvent;and water.
 25. An inkjet recording method, comprising: using an inkjetrecording apparatus which comprises. a black ink ejecting portionconfigured to eject a black ink containing a self-dispersion pigment;and color ink ejecting portions configured to eject, respectively, acyan ink, a magenta ink and a yellow ink which comprise a polymeremulsion which comprises a polymer fine particle containing a coloringmaterial which is insoluble in water or slightly soluble in water; and arecording-controlling unit configured to control recording, wherein theblack ink ejecting portion and the color ink ejecting portion scanrelative to a recording medium, to thereby record an image on therecording medium, wherein, when a color image is recorded on a plainpaper sheet and a black color area in the color image is recorded, therecording-controlling unit controls recording on the recording mediumsuch that the black ink ejecting portion and the color ink ejectingportion are used in combination, wherein, when the color image isrecorded on the plain paper sheet and the black color area in the colorimage is recorded, the inkjet recording method controls recording suchthat the black ink and the color ink are used in combination.
 26. Theink;et recording method according to claim 25, wherein when a monochromeimage is recorded on the plain paper sheet, the recording is carried outsuch that the black ink is used, leaving the color ink substantiallyfree from being used.
 27. The inkjet recording method according to claim25, wherein when a monochrome image is recorded on the plain papersheet, the recording is carried out such that the black ink and thecolor ink are used in combination.
 28. The inkjet recording methodaccording to claim 25, wherein a density of the ink is 5 mPa.sec or moreat 25° C.
 29. The inkjet recording method according to claim 25, whereinthe color ink comprises: the polymer emulsion which comprises thepolymer fine particle containing the coloring material which isinsoluble in water or slightly soluble in water; at least one wettingagent selected from the group consisting of glycerin, 1,3-butanediol,triethylene glycol, 1,6-hexanediol, propylene glycol, 1,5-pentanediol,diethylene glycol, dipropylene glycol, trimethylol propane, andtrimethylol ethane; at least one of a polyol having 8 to 11 carbonatoms, and a glycol ether having 8 to 11 carbon atoms; one of an anionicsurfactant and a nonionic surfactant; a water-soluble organic solvent;and water.
 30. The inkjet recording method according to claim 25,wherein the black ink comprises: the self-dispersion pigment; at leastone wetting agent selected from the group consisting of glycerin,1,3-butanecdiol, triethylene glycol, 1,6-hexanediol, propylene glycol,1,5-pentanediol, diethylene glycol, dipropylene glycol, trimethylolpropane, and trimethylol ethane; at least one of a polyol having 8 to 11carbon atoms, and a glycol ether having 8 to 11 carbon atoms; one of ananionic surfactant and a nonionic surfactant; a water-soluble organicsolvent; and water.
 31. An inkjet recording apparatus, comprising: ablack ink ejecting portion configured to eject a black ink containing aself-dispersion pigment; color ink ejecting portions configured toeject, respectively, a cyan ink, a magenta ink and a yellow ink whichcomprise a polymer emulsion which comprises a polymer fine particlecontaining a coloring material which is insoluble in water or slightlysoluble in water; and a recording-controlling unit configured to controlrecording, wherein the black ink ejecting portion and the color inkejecting portion scan relative to a recording medium, to thereby recordan image on the recording medium, wherein, when the recording medium isprovided, on an opaque base material thereof, with an ink acceptinglayer which has a surface free from a gloss and a black color area inthe color image is recorded, the recording-controlling unit controlsrecording such that the black ink ejecting portion and the color inkejecting portion are used in combination.
 32. The inkjet recordingapparatus according to claim 31, wherein when recording a monochromeimage on the recording medium which is provided, on the opaque basematerial thereof, with the ink accepting layer which has the surfacefree from the gloss, the recording-controlling unit carries out thecontrolling such that the black ink ejecting portion is used for therecording, leaving the color ink ejecting portion substantially freefrom being used.
 33. The inkjet recording apparatus according to claim31, wherein when recording a monochrome image on the recording mediumwhich is provided, on the opaque base material thereof, with the inkaccepting layer which has the surface free from the gloss, therecording-controlling unit carries out the controlling such that theblack ink ejecting portion and the color ink ejecting portion are usedin combination for the recording.
 34. The inkjet recording apparatusaccording to claim 31, wherein a density of the ink is 5 mPa.sec or moreat 25° C.
 35. The inkjet recording apparatus according to claim 31,wherein the color ink comprises: the polymer emulsion which comprisesthe polymer fine particle containing the coloring material which isinsoluble in water or slightly soluble in water; at least one wettingagent selected from the group consisting of glycerin, 1,3-butanediol,triethylene glycol, 1,6-hexanediol, propylene glycol, 1,5-pentanediol,diethylene glycol, dipropylene glycol, trimethylol propane, andtrimethylol ethane; at least one of a polyol having 8 to 11 carbonatoms, and a glycol ether having 8 to 11 carbon atoms; one of an anionicsurfactant and a nonionic surfactant; a water-soluble organic solvent;and water.
 36. The inkjet recording apparatus according to claim 31,wherein the black ink comprises: the self-dispersion pigment; at leastone wetting agent selected from the group consisting of glycerin,1,3-butanediol, triethylene glycol, 1,6-hexanediol, propylene glycol,1,5-pentanediol, diethylene glycol, dipropylene glycol, trimethylolpropane, and trimethylol ethane; at least one of a polyol having 8 to 11carbon atoms, and a glycol ether having 8 to 11 carbon atoms; one of ananionic surfactant and a nonionic surfactant; a water-soluble organicsolvent; and water.
 37. An inkjet recording method using an inkjetrecording apparatus which comprises: a black ink ejecting portionconfigured to eject a black ink containing a self-dispersion pigment;color ink ejecting portions configured to eject, respectively, a cyanink, a magenta ink and a yellow ink which comprise a polymer emulsionwhich comprises a polymer fine particle containing a coloring materialwhich is insoluble in water or slightly soluble in water; and arecording-controlling unit configured to control recording, wherein theblack ink ejecting portion and the color ink ejecting portion scanrelative to a recording medium, to thereby record an image on therecording medium, wherein, when the recording medium is provided, on anopaque base material thereof, with an ink accepting layer which has asurface free from a gloss and a black color area in the color image isrecorded, the recording-controlling unit controls recording such thatthe black ink ejecting portion and the color ink ejecting portion areused in combination, wherein, when recording the color image on therecording medium which is provided, on the opaque base material thereof,with the ink accepting layer which has the surface free from the gloss,and when the black color area in the color image is recorded, the inkjetrecording method controls recording such that the black ink and thecolor ink are used in combination.
 38. The inkjet recording methodaccording to claim 37, wherein when a monochrome image is recorded onthe recording medium which is provided, on the opaque base materialthereof, with the ink accepting layer which has the surface free fromthe gloss, the recording is carried out such that the black ink is used,leaving the color ink substantially free from being used.
 39. The ink;etrecording method according to claim 37, wherein when a monochrome imageis recorded on the recording medium which is provided, on the opaquebase material thereof, with the ink accepting layer which has thesurface free from the gloss, the recording is carried out such that theblack ink and the color ink are used in combination.
 40. The inkjetrecording method according to claim 37, wherein a density of the ink is5 mPa.sec or more at 25° C.
 41. The inkjet recording method according toclaim 37, wherein the color ink comprises: the polymer emulsion whichcomprises the polymer fine particle containing the coloring materialwhich is insoluble in water or slightly soluble in water; at least onewetting agent selected from the group consisting of glycerin,1,3-butanecdiol, triethylene glycol, 1,6-hexanediol, propylene glycol,1,5-pentanediol, diethylene glycol, dipropylene glycol, trimethylolpropane, and trimethylol ethane; at least one of a polyol having 8 to 11carbon atoms, and a glycol ether having 8 to 11 carbon atoms; one of ananionic surfactant and a nonionic surfactant; a water-soluble organicsolvent; and water.
 42. The inkjet recording method according to claim37, wherein the black ink comprises: the self-dispersion pigment; atleast one wetting agent selected from the group consisting of glycerin,1,3-butanediol, triethylene glycol, 1,6-hexanediol, propylene glycol,1,5-pentanediol, diethylene glycol, dipropylene glycol, trimethylolpropane, and trimethylol ethane; at least one of a polyol having 8 to 11carbon atoms, and a glycol ether having 8 to 11 carbon atoms; one of ananionic surfactant and a nonionic surfactant; a water-soluble organicsolvent; and water.
 43. An inkjet recording apparatus, comprising: ablack ink ejecting portion configured to eject a black ink containing aself-dispersion pigment; color ink ejecting portions configured toeject, respectively, a cyan ink, a magenta ink and a yellow ink whichcomprise a polymer emulsion which comprises a polymer fine particlecontaining a coloring material which is insoluble in water or slightlysoluble in water; and a recording-controlling unit configured to controlrecording, wherein the black ink ejecting portion and the color inkejecting portion scan relative to a recording medium, to thereby recordan image on the recording medium, wherein, when the recording is carriedout on the recording medium which is in at least one of the followingcases: the recording medium is optically transparent and is provided, ona transparent base material thereof, with an ink accepting layer, andthe recording medium is provided, on an opaque base material thereof,with an ink accepting layer which has a surface having a gloss, therecording-controlling unit controls recording on the recording mediumsuch that the color ink ejecting portion is used for recording amonochrome image and a color image which has a plurality of colors,leaving the black ink ejecting portion substantially free from beingused, wherein, when a black color area in the color image is recorded inat least one of the following cases: the color image is recorded on aplain paper sheet, and the color image is recorded on the recordingmedium which is provided, on an opaque base material thereof, with anink accepting layer which has a surface free from a gloss, therecording-controlling unit controls recording such that the black inkejecting portion and the color ink ejecting portion are used incombination, and wherein, in at least one of the following cases:recording the monochrome image on the plain paper sheet, and recordingthe monochrome image on the recording medium which is provided, on theopaque base material thereof, with the ink accepting layer which has thesurface free from the gloss, the recording-controlling unit controlsrecording such that the black ink ejecting portion is used, leaving thecolor ink ejecting portion substantially free from being used.
 44. Theinkjet recording apparatus according to claim 43, wherein a density ofthe ink is 5 mPa.sec or more at 25° C.
 45. The inkjet recordingapparatus according to claim 43, wherein the color ink comprises: thepolymer emulsion which comprises the polymer fine particle containingthe coloring material which is insoluble in water or slightly soluble inwater; at least one wetting agent selected from the group consisting ofglycerin, 1,3-butanediol, triethylene glycol, 1,6-hexanediol, propyleneglycol, 1,5-pentanediol, diethylene glycol, dipropylene glycol,trimethylol propane, and trimethylol ethane; at least one of a polyolhaving 8 to 11 carbon atoms, and a glycol ether having 8 to 11 carbonatoms; one of an anionic surfactant and a nonionic surfactant; awater-soluble organic solvent; and water.
 46. The inkjet recordingapparatus according to claim 43, wherein the black ink comprises: theself-dispersion pigment; at least one wetting agent selected from thegroup consisting of glycerin, 1,3-butanediol, triethylene glycol,1,6-hexanediol, propylene glycol, 1,5-pentanediol, diethylene glycol,dipropylene glycol, trimethylol propane, and trimethylol ethane; atleast one of a polyol having 8 to 11 carbon atoms, and a glycol etherhaving 8 to 11 carbon atoms; one of an anionic surfactant and a nonionicsurfactant; a water-soluble organic solvent; and water.
 47. An inkjetrecording method using an inkjet recording apparatus which comprises: ablack ink ejecting portion configured to eject a black ink containing aself-dispersion pigment; color ink ejecting portions configured toeject, respectively, a cyan ink, a magenta ink and a yellow ink whichcomprise a polymer emulsion which comprises a polymer fine particlecontaining a coloring material which is insoluble in water or slightlysoluble in water; and a recording-controlling unit configured to controlrecording, wherein the black ink ejecting portion and the color inkejecting portion scan relative to a recording medium, to thereby recordan image on the recording medium, wherein, when the recording is carriedout on the recording medium which is in at least one of the followingcases: the recording medium is optically transparent and is provided, ona transparent base material thereof, with an ink accepting layer, andthe recording medium is provided, on an opaque base material thereof,with an ink accepting layer which has a surface having a gloss, therecording-controlling unit controls recording on the recording mediumsuch that the color ink ejecting portion is used for recording amonochrome image and a color image which has a plurality of colors,leaving the black ink ejecting portion substantially free from beingused, wherein, when a black color area in the color image is recorded inat least one of the following cases: the color image is recorded on aplain paper sheet, and the color image is recorded on the recordingmedium which is provided, on an opaque base material thereof, with anink accepting layer which has a surface free from a gloss, therecording-controlling unit controls recording such that the black inkejecting portion and the color ink ejecting portion are used incombination, and wherein, in at least one of the following cases:recording the monochrome image on the plain paper sheet, and recordingthe monochrome image on the recording medium which is provided, on theopaque base material thereof, with the ink accepting layer which has thesurface free from the gloss, the recording-controlling unit controlsrecording such that the black ink ejecting portion is used, leaving thecolor ink ejecting portion substantially free from being used, wherein,in at least one of the following cases: the recording medium isoptically transparent and is provided, on the transparent base materialthereof, with the ink accepting layer, and the recording medium isprovided, on the opaque base material thereof, with the ink acceptinglayer which has the surface having the gloss, the inkjet recordingmethod controls recording on the recording medium such that the colorink is used for recording the monochrome image and the color image whichhas a plurality of colors, leaving the black ink substantially free frombeing used, wherein, when the black color area in the color image isrecorded in at least one of the following cases: the color image isrecorded on the plain paper sheet, and the color image is recorded onthe recording medium which is provided, on the opaque base materialthereof, with the ink accepting layer which has the surface free fromthe gloss, the inkjet recording method controls recording such that theblack ink and the color ink are used in combination, and wherein, in thefollowing case: recording the monochrome image, the inkjet recordingmethod controls recording such that the black ink is used, leaving thecolor ink substantially free from being used.
 48. The inkjet recordingmethod according to claim 47, wherein a density of the ink is 5 mPa.secor more at 25° C.
 49. The inkjet recording method according to claim 47,wherein the color ink comprises: the polymer emulsion which comprisesthe polymer fine particle containing the coloring material which isinsoluble in water or slightly soluble in water; at least one wettingagent selected from the group consisting of glycerin, 1,3-butanediol,triethylene glycol, 1,6-hexanediol, propylene glycol, 1,5-pentanediol,diethylene glycol, dipropylene glycol, trimethylol propane, andtrimethylol ethane; at least one of a polyol having 8 to 11 carbonatoms, and a glycol ether having 8 to 11 carbon atoms; one of an anionicsurfactant and a nonionic surfactant; a water-soluble organic solvent;and water.
 50. The inkjet recording method according to claim 47,wherein the black ink comprises: the self-dispersion pigment; at leastone wetting agent selected from the group consisting of glycerin,1,3-butanediol, triethylene glycol, 1,6-hexanediol, propylene glycol,1,5-pentanediol, diethylene glycol, dipropylene glycol, trimethylolpropane, and trimethylol ethane; at least one of a polyol having 8 to 11carbon atoms, and a glycol ether having 8 to 11 carbon atoms; one of ananionic surfactant and a nonionic surfactant; a water-soluble organicsolvent; and water.
 51. An inkjet recording apparatus, comprising: ablack ink ejecting portion configured to eject a black ink containing aself-dispersion pigment, and a polymer emulsion as a fixing agent; colorink ejecting portions configured to eject, respectively, a cyan ink, amagenta ink and a yellow ink which comprise a polymer emulsion whichcomprises a polymer fine particle containing a coloring material whichis insoluble in water or slightly soluble in water; and arecording-controlling unit configured to control recording, wherein theblack ink ejecting portion and the color ink ejecting portion scanrelative to a recording medium, to thereby record an image on therecording medium, wherein when a black color area in the color image isrecorded in any one of the following cases: i) the recording medium isoptically transparent and is provided, on a transparent base materialthereof, with an ink accepting layer, ii) the recording medium isprovided, on an opaque base material thereof, with an ink acceptinglayer which has a surface having a gloss, iii) a color image is recordedon a plain paper sheet, and iv) the recording medium for recording thecolor image is provided, on an opaque base material thereof, with an inkaccepting layer which has a surface free from a gloss, therecording-controlling unit controls recording such that the black inkejecting portion and the color ink ejecting portion are used incombination.
 52. The inkjet recording apparatus according to claim 51,wherein when recording a monochrome image on the recording medium, therecording-controlling unit carries out the controlling such that theblack ink ejecting portion is used for the recording, leaving the colorink ejecting portion substantially free from being used.
 53. The inkjetrecording apparatus according to claim 51, wherein when recording amonochrome image on the recording medium, the recording-controlling unitcarries out the controlling such that the black ink ejecting portion andthe color ink ejecting portion are used in combination for therecording.
 54. The inkjet recording apparatus according to claim 51,wherein a density of the ink is 5 mPa.sec or more at 25° C.
 55. Theinkjet recording apparatus according to claim 51, wherein the color inkcomprises: the polymer emulsion which comprises the polymer fineparticle containing the coloring material which is insoluble in water orslightly soluble in water; at least one wetting agent selected from thegroup consisting of glycerin, 1,3-butanediol, triethylene glycol,1,6-hexanediol, propylene glycol, 1,5-pentanediol, diethylene glycol,dipropylene glycol, trimethylol propane, and trimethylol ethane; atleast one of a polyol having 8 to 11 carbon atoms, and a glycol etherhaving 8 to 11 carbon atoms; one of an anionic surfactant and a nonionicsurfactant; a water-soluble organic solvent; and water.
 56. The inkjetrecording apparatus according to claim 51, wherein the black inkcomprises: the self-dispersion pigment; at least one wetting agentselected from the group consisting of glycerin, 1,3-butanediol,triethylene glycol, 1,6-hexanediol, propylene glycol, 1,5-pentanediol,diethylene glycol, dipropylene glycol, trimethylol propane, andtrimethylol ethane; at least one of a polyol having 8 to 11 carbonatoms, and a glycol ether having 8 to 11 carbon atoms; one of an anionicsurfactant and a nonionic surfactant; a water-soluble organic solvent;and water.
 57. An inkjet recording method using an inkjet recordingapparatus which comprises: a black ink ejecting portion configured toeject a black ink containing a self-dispersion pigment, and a polymeremulsion as a fixing agent; color ink ejecting portions configured toeject, respectively, a cyan ink, a magenta ink and a yellow ink whichcomprise a polymer emulsion which comprises a polymer fine particlecontaining a coloring material which is insoluble in water or slightlysoluble in water; and a recording-controlling unit configured to controlrecording, wherein the black ink ejecting portion and the color inkejecting portion scan relative to a recording medium, to thereby recordan image on the recording medium, wherein when a black color area in thecolor image is recorded in any one of the following cases: i) therecording medium is optically transparent and is provided, on atransparent base material thereof, with an ink accepting layer, ii) therecording medium is provided, on an opaque base material thereof, withan ink accepting layer which has a surface having a gloss, iii) a colorimage is recorded on a plain paper sheet, and iv) the recording mediumfor recording the color image is provided, on an opaque base materialthereof, with an ink accepting layer which has a surface free from agloss, the recording-controlling unit controls recording such that theblack ink ejecting portion and the color ink ejecting portion are usedin combination, wherein when the black color area in the color image isrecorded in any one of the following cases: i) the recording medium isoptically transparent and is provided, on the transparent base materialthereof, with the ink accepting layer, ii) the recording medium isprovided, on the opaque base material thereof, with the ink acceptinglayer which has the surface having the gloss, iii) the color image isrecorded on the plain paper sheet, and iv) the recording medium forrecording the color image is provided, on the opaque base materialthereof, with the ink accepting layer which has the surface free fromthe gloss, the inkjet recording method controls recording such that theblack ink ejecting portion and the color ink ejecting portion are usedin combination.
 58. The inkjet recording method according to claim 57,wherein when a monochrome image is recorded on the recording medium, therecording is carried out such that the black ink is used, leaving thecolor ink substantially free from being used.
 59. The inkjet recordingmethod according to claim 57, wherein when a monochrome image isrecorded on the recording medium, the recording is carried out such thatthe black ink and the color ink are used in combination.
 60. The inkjetrecording method according to claim 57, wherein a density of the ink is5 mPa.sec or more at 25° C.
 61. The inkjet recording method according toclaim 57, wherein the color ink comprises: the polymer emulsion whichcomprises the polymer fine particle containing the coloring materialwhich is insoluble in water or slightly soluble in water; at least onewetting agent selected from the group consisting of glycerin,1,3-butanediol, triethylene glycol, 1,6-hexanediol, propylene glycol,1,5-pentanediol, diethylene glycol, dipropylene glycol, trimethylolpropane, and trimethylol ethane; at least one of a polyol having 8 to 11carbon atoms, and a glycol ether having 8 to 11 carbon atoms; one of ananionic surfactant and a nonionic surfactant; a water-soluble organicsolvent; and water.
 62. The inkjet recording method according to claim57, wherein the black ink comprises: the self-dispersion pigment; atleast one wetting agent selected from the group consisting of glycerin,1,3-butanediol, triethylene glycol, 1,6-hexanediol, propylene glycol,1,5-pentanediol, diethylene glycol, dipropylene glycol, trimethylolpropane, and trimethylol ethane; at least one of a polyol having 8 to 11carbon atoms, and a glycol ether having 8 to 11 carbon atoms; one of ananionic surfactant and a nonionic surfactant; a water-soluble organicsolvent; and water.